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Provide reliable energy and energy-related services in a safe, reliable and environmentally responsible manner to our stakeholders through our ownership in ONEOK Partners - environmental, safety and health issues continue to be a primary focus for us, and our emphasis on personal and process safety has produced improvements in the key indicators we track. We also continue to look for ways to reduce our environmental impact by conserving resources and utilizing more efficient technologies;

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Maximize dividend payout while maintaining prudent financial strength and flexibility - during 2015, cash dividends paid per share increased 14 percent compared with the prior year. During 2015, ONEOK Partners’ cash distributions paid increased by 15 cents per unit, an increase of approximately 5 percent compared with 2014. ONEOK Partners has a predominantly fee-based business in the Natural Gas Liquids and Natural Gas Pipelines segments and has significantly increased the fee component in the Natural Gas Gathering and Processing segment’s contracts. ONEOK Partners is investing in growth projects to meet the needs of crude oil and natural gas producers. Through its Roadrunner joint venture, ONEOK Partners is also investing in natural gas pipeline infrastructure from West Texas to the Mexican border that is expected to provide markets in Mexico access to upstream supply basins. When completed, ONEOK Partners’ capital projects are anticipated to provide additional fee-based earnings and cash flows; and

•	Attract, select, develop and retain a diverse group of employees to support strategy execution - we continue to execute on our recruiting strategy that targets professional and field personnel in our operating areas. We also continue to focus on employee development efforts with our current employees and monitor our benefits and compensation package to remain competitive.

•	Natural Gas Gathering and Processing;

•	Natural Gas Liquids; and

•	Natural Gas Pipelines.

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POP with fee-based components - Under this type of contract, ONEOK Partners charges fees for gathering, treating, compressing and processing the producer’s natural gas and retains a percentage of the proceeds from the sale of residue natural gas, condensate and/or NGLs. This type of contract represented approximately 90 percent and 87 percent of contracted volumes in this segment for 2015 and 2014, respectively. There are a variety of factors that directly affect ONEOK Partners’ POP with fee revenues, including:

–	the price of natural gas, crude oil and NGLs;

–	the percentage of NGL, condensate and residue natural gas sales proceeds retained by ONEOK Partners that it receives as part of the compensation for the services it provides;

–	the composition of the natural gas and NGLs produced;

–	the fees ONEOK Partners charges for its services;

–	the volume produced; and

–	the costs ONEOK Partners incurs to provide its services.

•	Fee-only - Under this type of contract, ONEOK Partners is paid a fee for the services it provides, based on volumes gathered, processed, treated and/or compressed. ONEOK Partners’ fee-only contracts represented approximately 10 percent and 13 percent of contracted volumes in this segment for 2015 and 2014, respectively.

•	49 percent ownership in Bighorn Gas Gathering, which operates a coal-bed methane gathering system in the Powder River Basin;

•	37 percent ownership in Fort Union Gas Gathering, which gathers coal-bed methane produced in the Powder River Basin and delivers it to the interstate pipeline system;

•	35 percent ownership interest in Lost Creek Gathering Company, which gathers natural gas produced from conventional dry natural gas wells in the Wind River Basin of central Wyoming and delivers it to the interstate pipeline system; and

•	10 percent ownership interest in Venice Energy Services Co., a natural gas processing facility near Venice, Louisiana.

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•	the opportunity to capture additional natural gas currently being flared by producers with additional natural gas compression and processing capacity on ONEOK Partners’ systems due to projects placed in service in late 2015 and projects that are expected to be completed in 2016;

•	the connection of wells that have been drilled but not yet completed or connected to ONEOK Partners’ systems;

•	producers focusing their drilling in the most productive areas, in which ONEOK Partners has significant gathering and processing assets, which typically produce at higher initial production rates compared with other areas, have the highest natural gas content and have slower natural gas declines than crude oil;

•	the use by producers of more efficient drilling rigs; and

•	continued improvements in production results by producers due to enhanced completion techniques.

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•	quality of services provided;

•	producer drilling activity;

•	products retained and/or fees charged under its gathering and processing contracts;

•	location of its gathering systems relative to those of its competitors;

•	location of its gathering systems relative to drilling activity;

•	operating pressures maintained on its gathering systems;

•	efficiency and reliability of its operations;

•	delivery capabilities for natural gas and NGLs that exist in each system and plant location; and

•	cost of capital.

•	improving natural gas processing efficiency;

•	reducing operating costs;

•	consolidating assets;

•	decreasing commodity price exposure; and

•	restructuring low-margin contracts.

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ONEOK Partners’ exchange-services activities utilize its assets to gather, fractionate and/or treat unfractionated NGLs, thereby converting them into marketable NGL products that are stored and shipped to a market center or customer-designated location. Many of these exchange volumes are under contracts with minimum volume commitments. ONEOK Partners’ exchange services activities are primarily fee-based.

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ONEOK Partners’ transportation and storage services transport unfractionated NGLs, NGL products and refined petroleum products, primarily under FERC-regulated tariffs. Tariffs specify the maximum rates ONEOK Partners charges its customers and the general terms and conditions for NGL transportation service on its pipelines. ONEOK Partners’ storage activities consist primarily of fee-based NGL storage services at its Mid-Continent and Gulf Coast storage facilities.

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ONEOK Partners’ optimization and marketing activities utilize its assets, contract portfolio and market knowledge to capture location, product and seasonal price differentials. It primarily transports NGL products between Conway, Kansas, and Mont Belvieu, Texas, to capture the location price differentials between the two market centers. Its natural gas liquids storage facilities also are utilized to capture seasonal price differentials. A growing portion of its marketing activities serves truck and rail markets.

•	ONEOK Partners’ isomerization activities capture the price differential when normal butane is converted into the more valuable iso-butane at its isomerization unit in Conway, Kansas.

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•	50 percent ownership interest in Overland Pass Pipeline Company, which operates an interstate natural gas liquids pipeline system extending approximately 760 miles, originating in Wyoming and Colorado and terminating in Kansas;

•	50 percent ownership interest in Chisholm Pipeline Company, which operates an interstate natural gas liquids pipeline system extending approximately 185 miles from origin points in Oklahoma and terminating in Kansas; and

•	50 percent ownership interest in Heartland Pipeline Company, which operates a terminal and pipeline system that transports refined petroleum products in Kansas, Nebraska and Iowa.

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•	quality of services provided;

•	producer drilling activity;

•	the petrochemical industry’s level of capacity utilization and feedstock requirements;

•	fees charged under its contracts;

•	current and forward NGL prices;

•	location of its gathering systems relative to its competitors;

•	location of its gathering systems relative to drilling activity;

•	proximity to NGL supply areas and markets;

•	efficiency and reliability of its operations;

•	receipt and delivery capabilities that exist in each pipeline system, plant, fractionator and storage location; and

•	cost of capital.

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•	Midwestern Gas Transmission, which is a bidirectional system that interconnects with Tennessee Gas Transmission Company’s pipeline near Portland, Tennessee, and with several interstate pipelines at the Chicago Hub near Joliet, Illinois;

•	Viking Gas Transmission, which is a bidirectional system that interconnects with a TransCanada Corporation pipeline near Emerson, Manitoba, and ANR Pipeline Company near Marshfield, Wisconsin;

•	Guardian Pipeline, which interconnects with several pipelines at the Chicago Hub near Joliet, Illinois, and with local natural gas distribution companies in Wisconsin; and

•	OkTex Pipeline, which has interconnections with several pipelines in Oklahoma, Texas and New Mexico.

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Firm service - Customers reserve a fixed quantity of pipeline capacity for a specified period of time, which obligates the customer to pay regardless of usage. Under this type of contract, the customer pays a monthly fixed fee and incremental fees, known as commodity charges, which are based on the actual volumes of natural gas they transport or store. In addition, ONEOK Partners may retain a percentage of fuel in-kind based on the volumes of natural gas transported. Under the firm service contract, the customer generally is guaranteed access to the capacity they reserve.

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Interruptible service - Under interruptible service transportation agreements, the customer may utilize available capacity after firm service requests are satisfied. The customer is not guaranteed use of ONEOK Partners’ pipelines unless excess capacity is available. Customers typically are assessed fees, such as a commodity charge, and ONEOK Partners may retain a specified volume of natural gas in-kind based on their actual usage.

•	Firm Service - Customers reserve a specific quantity of storage capacity, including injection and withdrawal rights, and generally pay fixed fees based on the quantity of capacity reserved plus an injection and withdrawal fee. Firm storage contracts typically have terms longer than one year.

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•	Park-and-Loan Service - An interruptible service offered to customers providing the ability to park (inject) or loan (withdraw) natural gas into or out of storage, typically for monthly terms. Customers reserve the right to park or loan natural gas based on a specified quantity, including injection and withdrawal rights when capacity is available.

•	50 percent interest in Northern Border Pipeline, which owns a FERC-regulated interstate pipeline that transports natural gas from the Montana-Saskatchewan border near Port of Morgan, Montana, to a terminus near North Hayden, Indiana.

•	50 percent interest in Roadrunner, which is currently under construction, with Phase I expected to be completed in the first quarter 2016. The Roadrunner pipeline will transport natural gas from the Permian Basin in West Texas to the Mexican border near El Paso, Texas.

•	Weather - The effect of weather on its natural gas pipelines operations is discussed below under “Seasonality.”

•	Economy - The strength of the economy directly impacts manufacturing and industrial companies that consume natural gas.

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Price volatility - Commodity price volatility can influence producers’ decisions related to the production of natural gas. This segment’s pipeline customers, primarily natural gas and electric utilities, require natural gas to operate their businesses and generally are not impacted by location price differentials. However, narrower location price differentials may impact demand for the segment’s services from natural gas marketers as discussed below under “Commodity Prices.”

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Regulatory - Demand for this segment’s services is also affected as coal-fired electric generators are retired and replaced with alternative power generation fuels such as natural gas. EPA regulations on emissions from coal-fired electric-generation plants, including the Maximum Achievable Control Technology Standards and the Mercury and Air Toxics Standards, have increased the demand for natural gas as a fuel for electric generation, as well as related transportation and storage services. The demand for natural gas and related transportation and storage services is expected to increase over the next several years as these regulations continue to be implemented.

•	Transportation - ONEOK Partners is exposed to market risk through interruptible contracts or when existing firm contracts expire and are subject to renegotiation with customers that have competitive alternatives.

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•	Storage - Natural gas storage revenue is impacted by the differential between forward pricing of natural gas physical contracts and the price of natural gas on the spot market.

•	Fuel - ONEOK Partners’ fuel costs and the value of the retained fuel in-kind received for its services also are impacted by changes in the price of natural gas.

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•	an evaluation on whether hazardous natural gas liquids and natural gas pipeline integrity-management requirements should be expanded beyond current high-consequence areas;

•	a review of all natural gas and hazardous natural gas liquids gathering pipeline exemptions;

•	a verification of records for pipelines in Class 3 and 4 locations and high-consequence areas to confirm maximum allowable operating pressures; and

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•	a requirement to test previously untested pipelines operating above 30 percent yield strength in high-consequence areas.

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•	make it more difficult for us to satisfy our obligations with respect to our senior notes and our other indebtedness due to the increased debt-service obligations, which could, in turn, result in an event of default on such other indebtedness or our senior notes;

•	impair our ability to obtain additional financing in the future for working capital, capital expenditures, acquisitions or general business purposes;

•	diminish our ability to withstand a downturn in our business or the economy;

•	require us to dedicate a substantial portion of our cash flow from operations to debt-service payments, reducing the availability of cash for working capital, capital expenditures, acquisitions, dividends or general corporate purposes;

•	limit our flexibility in planning for, or reacting to, changes in our business and the industry in which ONEOK Partners operates; and

•	place us at a competitive disadvantage compared with our competitors that have proportionately less debt.

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•	the extent to which acquisitions and investment opportunities become available;

•	success in bidding for the opportunities that do become available;

•	regulatory approval, if required, of the acquisitions or investments on favorable terms; and

•	access to capital, including the ability to use our or equity in acquisitions or investments, and the terms upon which we obtain capital.

•	inaccurate assumptions about volumes, revenues and costs, including potential synergies;

•	an inability to integrate successfully the businesses we acquire;

•	decrease in our liquidity as a result of our using a significant portion of our available cash or borrowing capacity to finance the acquisition;

•	a significant increase in our interest expense and/or financial leverage if we incur additional debt to finance the acquisition;

•	the assumption of unknown liabilities for which we are not indemnified, our indemnity is inadequate or our insurance policies may exclude from coverage;

•	an inability to hire, train or retain qualified personnel to manage and operate the acquired business and assets;

•	limitations on rights to indemnity from the seller;

•	inaccurate assumptions about the overall costs of equity or debt;

•	the diversion of management’s and employees’ attention from other business concerns;

•	unforeseen difficulties operating in new product areas or new geographic areas;

•	increased regulatory burdens;

•	customer or key employee losses at an acquired business; and

•	increased regulatory requirements.

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•	controlling ONEOK Partners’ plants and pipelines with industrial control systems including Supervisory Control and Data Acquisition (SCADA);

•	collecting and storing customer, employee, investor and other stakeholder information and data;

•	processing transactions;

•	summarizing and reporting results of operations;

•	hosting, processing and sharing confidential and proprietary research, business plans and financial information;

•	complying with regulatory, legal or tax requirements;

•	providing data security; and

•	handling other processing necessary to manage our business.

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•	overall domestic and global economic conditions;

•	relatively minor changes in the supply of, and demand for, domestic and foreign energy;

•	market uncertainty;

•	the availability and cost of third-party transportation, natural gas processing and fractionation capacity;

•	the level of consumer product demand and storage inventory levels;

•	ethane rejection;

•	geopolitical conditions impacting supply and demand for natural gas, NGLs and crude oil;

•	weather conditions;

•	domestic and foreign governmental regulations and taxes;

•	the price and availability of alternative fuels;

•	speculation in the commodity futures markets;

•	the effects of imports and exports on the price of natural gas, crude oil, NGL and liquefied natural gas;

•	the effect of worldwide energy-conservation measures; and

•	the impact of new supplies, new pipelines, processing and fractionation facilities on location price differentials.

•	demand and prices for natural gas, NGLs and crude oil;

•	producers’ access to capital;

•	producers’ finding and development costs of reserves;

•	producers’ desire and ability to obtain necessary permits in a timely and economic manner;

•	natural gas field characteristics and production performance;

•	surface access and infrastructure issues; and

•	capacity constraints on natural gas, crude oil and natural gas liquids infrastructure from the producing areas and ONEOK Partners’ facilities.

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•	the value of the NGLs and natural gas it receives as a portion of its compensation for the natural gas gathering and processing services it provides;

•	the price differentials between the individual NGL products with respect to ONEOK Partners’ NGL transportation and fractionation agreements;

•	the location price differentials in the price of natural gas and NGLs with respect to ONEOK Partners’ natural gas and NGL transportation businesses;

•	the seasonal price differentials of natural gas and NGLs related to storage operations; and

•	the fuel costs and the value of the retained fuel in-kind in ONEOK Partners’ natural gas pipelines and storage operations.

•	projects may require significant capital expenditures, which may exceed ONEOK Partners’ estimates, and involves numerous regulatory, environmental, political, legal and weather-related uncertainties;

•	projects may increase demand for labor, materials and rights of way, which may, in turn, affect ONEOK Partners’ costs and schedule;

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•	ONEOK Partners may be unable to obtain new rights of way to connect new natural gas or NGL supplies to its existing gathering or transportation pipelines;

•	if ONEOK Partners undertakes these projects, it may not be able to complete them on schedule or at the budgeted cost;

•	ONEOK Partners’ revenues may not increase immediately upon the expenditure of funds on a particular project.  For instance, if ONEOK Partners builds a new pipeline, the construction will occur over an extended period of time, and it will not receive any material increases in revenues until after completion of the project;

•	ONEOK Partners’ may have only limited natural gas or NGL supply committed to these facilities prior to their construction;

•	ONEOK Partners may construct facilities to capture anticipated future growth in production in a region in which anticipated production growth does not materialize;

•	ONEOK Partners may rely on estimates of proved reserves in its decision to construct new pipelines and facilities, which may prove to be inaccurate because there are numerous uncertainties inherent in estimating quantities of proved reserves; and

•	ONEOK Partners may be required to rely on third parties downstream of its facilities to have available capacity for its delivered natural gas or NGLs, which may not yet be operational.

•	the level of existing and new competition in ONEOK Partners’ businesses or from alternative fuel sources, such as electricity, coal, fuel oils or nuclear energy;

•	natural gas and NGL prices, demand, availability; and

•	margins in ONEOK Partners’ markets.

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•	the Clean Air Act and analogous state laws that impose obligations related to air emissions;

•	the Clean Water Act and analogous state laws that regulate discharge of waste water from ONEOK Partners’ facilities to state and federal waters;

•	the federal CERCLA and analogous state laws that regulate the cleanup of hazardous substances that may have been released at properties currently or previously owned or operated by ONEOK Partners or locations to which ONEOK Partners has sent waste for disposal; and

•	the federal Resource Conservation and Recovery Act and analogous state laws that impose requirements for the handling and discharge of solid and hazardous waste from ONEOK Partners’ facilities.

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•	rates, operating terms and conditions of service;

•	the types of services ONEOK Partners may offer it customers;

•	construction of new facilities;

•	the integrity, safety and security of facilities and operations;

•	acquisition, extension or abandonment of services or facilities;

•	reporting and information posting requirements;

•	maintenance of accounts and records; and

•	relationships with affiliate companies involved in all aspects of the natural gas and energy businesses.

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•	make it more difficult to satisfy its obligations with respect to its senior notes and other indebtedness, which could in turn result in an event of default on such other indebtedness or its senior notes;

•	impair its ability to obtain additional financing in the future for working capital, capital expenditures, acquisitions or general business purposes;

•	diminish its ability to withstand a downturn in its business or the economy;

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•	require it to dedicate a substantial portion of its cash flow from operations to debt-service payments, thereby reducing the availability of cash for working capital, capital expenditures, acquisitions, distributions to partners and general partnership purposes;

•	limit its flexibility in planning for, or reacting to, changes in its business and the industry in which it operates; and

•	place it at a competitive disadvantage compared with its competitors that have proportionately less debt.

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•	the Intermediate Partnership incurred the guarantee with the intent to hinder, delay or defraud any of its present or future creditors or the Intermediate Partnership contemplated insolvency with a design to favor one or more creditors to the total or partial exclusion of others; or

•	the Intermediate Partnership did not receive fair consideration or reasonable equivalent value for issuing the guarantee and, at the time it issued the guarantee, the Intermediate Partnership:

–	was engaged or about to engage in a business or transaction for which its remaining assets constituted unreasonably small capital; or

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•	the sum of its debts, including contingent liabilities, were greater than the fair saleable value of all of its assets at a fair valuation;

•	the present fair saleable value of its assets was less than the amount that would be required to pay its probable liability on its existing debts, including contingent liabilities, as they become absolute and mature; or

•	it could not pay its debts as they become due.

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•	approximately 11,300 miles and 7,600 miles of natural gas gathering pipelines in the Mid-Continent and Rocky Mountain regions, respectively;

•	nine natural gas processing plants with approximately 785 MMcf/d of processing capacity in the Mid-Continent region, and 11 natural gas processing plants with approximately 965 MMcf/d of processing capacity in the Rocky Mountain region; and

•	approximately 15 MBbl/d of natural gas liquids fractionation capacity at various natural gas processing plants in the Mid-Continent and Rocky Mountain regions.

•	one additional natural gas processing plant in the Rocky Mountain region, which will provide approximately 80 MMcf/d of combined processing capacity; and

•	two de-ethanizers in the Rocky Mountain region, which will remove ethane from the natural gas stream, which we expect to be sold under a long-term contract to a customer who plans to transport the ethane on a third-party pipeline.

•	approximately 2,800 miles of non-FERC-regulated natural gas liquids gathering pipelines with peak capacity of approximately 800 MBbl/d;

•	approximately 170 miles of non-FERC-regulated natural gas liquids distribution pipelines with peak transportation capacity of approximately 66 MBbl/d;

•	approximately 4,300 miles of FERC-regulated natural gas liquids gathering pipelines with peak capacity of approximately 683 MBbl/d;

•	approximately 4,200 miles of FERC-regulated natural gas liquids and refined petroleum products distribution pipelines with peak capacity of 993 MBbl/d;

•	one natural gas liquids fractionator in Oklahoma with operating capacity of approximately 210 MBbl/d, two natural gas liquids fractionators in Kansas with combined operating capacity of 280 MBbl/d and two natural gas liquids fractionators in Texas with combined operating capacity of 150 MBbl/d;

•	80 percent ownership interest in one natural gas liquids fractionator in Texas with ONEOK Partners’ proportional share of operating capacity of approximately 128 MBbl/d;

•	interest in one natural gas liquids fractionator in Kansas with ONEOK Partners’ proportional share of operating capacity of approximately 11 MBbl/d;

•	one isomerization unit in Kansas with operating capacity of 9 MBbl/d;

•	six natural gas liquids storage facilities in Oklahoma, Kansas and Texas with operating storage capacity of approximately 23.2 MMBbl;

•	eight natural gas liquids product terminals in Missouri, Nebraska, Iowa and Illinois;

•	above- and below-ground storage facilities associated with ONEOK Partners’ FERC-regulated natural gas liquids pipeline operations in Iowa, Illinois, Nebraska and Kansas with combined operating capacity of 978 MBbl; and

•	one ethane/propane splitter in Texas with operating capacity of 32 MBbl/d of purity ethane and 8 MBbl/d of propane.

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•	its non-FERC-regulated natural gas liquids gathering pipelines were approximately 65 percent and 62 percent;

•	its FERC-regulated natural gas liquids gathering pipelines were approximately 75 percent and 79 percent;

•	its FERC-regulated natural gas liquids distribution pipelines were approximately 43 percent and 47 percent;

•	its natural gas liquids fractionators were approximately 66 percent and 70 percent; and

•	its average contracted natural gas liquids storage volumes were approximately 66 percent and 69 percent of storage capacity.

•	approximately 1,500 miles of FERC-regulated interstate natural gas pipelines with approximately 3.2 Bcf/d of peak transportation capacity;

•	approximately 5,200 miles of state-regulated intrastate transmission pipelines with peak transportation capacity of approximately 3.2 Bcf/d; and

•	approximately 55.4 Bcf of total active working natural gas storage capacity.

•	one intrastate transmission pipeline in the Permian Basin through a 50-50 joint venture, which will provide approximately 640 MMcf/d of transportation capacity; and

•	one wholly owned intrastate transmission pipeline expansion in the Permian Basin, which will provide 260 MMcf/d of incremental transportation capacity.

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ITEM 5.	MARKET FOR REGISTRANT’S COMMON EQUITY, RELATED STOCKHOLDER MATTERS AND ISSUER PURCHASES OF EQUITY SECURITIES

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ITEM 7.	MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

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•	a decrease of $209.7 million due primarily to lower net realized NGL, natural gas and condensate prices; and

•	a decrease of $10.4 million due primarily to decreased ethane rejection to maintain downstream NGL product specifications; offset partially by

•	an increase of $91.6 million due primarily to restructured contracts resulting in higher average fee rates and a lower percentage of proceeds retained from the sale of commodities under POP with fee contracts; and

•	an increase of $38.1 million due primarily to natural gas volume growth in the Williston Basin, offset partially by unplanned operational outages in the Williston Basin and decreased natural gas volumes in the Cana-Woodford Shale.

•	an increase of $13.8 million in higher outside service expenses due primarily to the completion of growth projects;

•	an increase of $10.5 million in employee-related costs due to higher labor and employee benefit costs resulting from the completion of growth projects; and

•	an increase of $3.1 million due to higher ad valorem taxes resulting from the completion of growth projects; offset partially by

•	a decrease of $12.7 million in materials and supplies due primarily to lower chemical costs.

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an increase of $147.6 million due primarily to natural gas volume growth in the Williston Basin and Cana-Woodford Shale and increased ownership of the Maysville, Oklahoma, natural gas processing plant resulting in higher natural gas volumes gathered, compressed, processed, transported and sold, higher NGL volumes sold and higher fees, offset partially by wellhead freeze-offs due to severely cold weather in the first quarter 2014;

•	an increase of $11.3 million due primarily to higher net realized natural gas and NGL prices; and

•	an increase of $8.8 million due primarily to higher average fee rates and a lower percentage of proceeds retained from the sale of commodities under POP with fee contracts; offset partially by

•	a decrease of $6.4 million due to a condensate contract settlement in 2013.

•	an increase of $46.3 million in higher materials and supplies, and outside service expenses; and

•	an increase of $21.2 million in employee-related costs due to higher labor and employee benefit costs; offset partially by

•	a decrease of $3.2 million due to lower ad valorem tax expense resulting from capitalized taxes related to construction projects.

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•	an increase of $191.0 million in fee-based exchange-services, which resulted from increased volumes from new plants connected in the Williston Basin and Mid-Continent region and higher revenues from customers with minimum volume obligations;

•	an increase of $81.8 million in the transportation business due primarily to the acquisition of the West Texas LPG system in the Permian Basin, which was acquired in November 2014; and

•	an increase of $23.8 million resulting from decreased ethane rejection in the Williston Basin resulting from downstream NGL product specification issues, offset partially by higher ethane rejection in the Mid-Continent region; offset partially by

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a decrease of $118.4 million in the optimization, marketing and differentials-based activities, which resulted from a $66.3 million decrease due primarily to narrower NGL product price differentials, a $27.7 million decrease due primarily to narrower NGL location price differentials and a $24.4 million decrease in the marketing business. A portion of this decrease relates to the increased demand for propane experienced during the first quarter 2014;

•	a decrease of $29.9 million related to lower isomerization volumes resulting from narrower NGL price differential between normal butane and iso-butane; and

•	a decrease of $6.9 million due to the impact of operational losses in 2015 and operational measurement gains in 2014.

•	an increase of $29.2 million due to the West Texas LPG acquisition; and

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•	an increase of $6.5 million due to higher ad valorem taxes; offset partially by

•	a decrease of $17.6 million due to reduced operating costs resulting from lower rates charged by service providers, primarily from $6.6 million lower outside services, $5.0 million lower supplies and expenses and $3.2 million lower chemicals and materials.

•	an increase of $157.4 million in fee-based exchange and transportation services, which resulted from increased volumes from new plants connected in the Williston Basin and Mid-Continent region, and higher fees for exchange-services activities resulting from contract renegotiations, offset partially by lower volumes from the termination of a contract;

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an increase of $79.8 million in the optimization, marketing and differentials-based activities, which resulted from a $31.4 million increase due primarily to wider realized NGL product price differentials; a $25.2 million increase in the marketing business related primarily to increased weather-related seasonal demand for propane during the first quarter 2014, and marketing and truck and rail activities in the second, third and fourth quarters 2014; and a $23.2 million increase due primarily to significantly wider NGL location price differentials, primarily related to increased weather-related seasonal demand for propane during the first quarter 2014, offset partially by lower optimization volumes in the second, third and fourth quarters 2014 when differentials narrowed; and

•	an increase of $22.8 million related to higher isomerization volumes resulting from the wider NGL product price differential between normal butane and iso-butane; offset partially by

•	a decrease of $18.3 million resulting from the impact of ethane rejection, which resulted in lower NGL volumes; and

•	a decrease of $6.0 million due to the impact of lower operational measurement gains.

•	an increase of $20.1 million due to higher outside services expenses associated primarily with scheduled maintenance and the growth of operations related to completed capital projects;

•	an increase of $15.5 million due to higher ad valorem taxes related to its completed capital projects;

•	an increase of $14.9 million due to higher employee-related costs due primarily to higher labor and employee benefit costs; and

•	an increase of $3.4 million due to higher chemical, materials and supplies expense.

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•	a decrease of $24.3 million from lower short-term natural gas storage services as a result of weather-related seasonal demand associated with severely cold weather in the first quarter 2014;

•	a decrease of $10.0 million from lower net retained fuel due to lower natural gas prices and natural gas volumes retained; and

•	a decrease of $5.0 million from lower park-and-loan services on ONEOK Partners’ interstate pipelines as a result of weather-related seasonal demand due to severely cold weather in the first quarter 2014; offset partially by

•	an increase of $8.6 million due to higher transportation revenues, primarily from increased rates on intrastate pipelines and higher rates on Viking Gas Transmission, offset partially by decreased interruptible transportation revenues from lower natural gas volumes transported.

•	an increase of $26.3 million due to higher transportation revenues primarily from increased rates on intrastate pipelines, higher contracted capacity and rates on Midwestern Gas Transmission and increased interruptible transportation revenues from higher natural gas volumes transported;

•	an increase of $17.6 million from higher short-term natural gas storage services due to higher park-and-loan activity as a result of weather-related seasonal demand primarily in the first quarter 2014 and greater capacity available for such services;

•	an increase of $5.1 million due to increased park-and-loan services on ONEOK Partners’ interstate pipelines as a result of weather-related seasonal demand in the first quarter 2014;

•	an increase of $5.0 million from higher net retained fuel due to higher natural gas prices and natural gas volumes retained; and

•	an increase of $3.1 million from additional storage services to meet utility customers’ peak-day demand; offset partially by

•	a decrease of $14.3 million due to lower storage revenues from lower contracted firm capacity.

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•	the effects of weather and other natural phenomena, including climate change, on our operations, demand for our services and energy prices;

•	competition from other United States and foreign energy suppliers and transporters, as well as alternative forms of energy, including, but not limited to, solar power, wind power, geothermal energy and biofuels such as ethanol and biodiesel;

•	the capital intensive nature of our businesses;

•	the profitability of assets or businesses acquired or constructed by us;

•	our ability to make cost-saving changes in operations;

•	risks of marketing, trading and hedging activities, including the risks of changes in energy prices or the financial condition of our counterparties;

•	the uncertainty of estimates, including accruals and costs of environmental remediation;

•	the timing and extent of changes in energy commodity prices;

•	the effects of changes in governmental policies and regulatory actions, including changes with respect to income and other taxes, pipeline safety, environmental compliance, climate change initiatives and authorized rates of recovery of natural gas and natural gas transportation costs;

•	the impact on drilling and production by factors beyond our control, including the demand for natural gas and crude oil; producers’ desire and ability to obtain necessary permits; reserve performance; and capacity constraints on the pipelines that transport crude oil, natural gas and NGLs from producing areas and our facilities;

•	difficulties or delays experienced by trucks, railroads or pipelines in delivering products to or from our terminals or pipelines;

•	changes in demand for the use of natural gas, NGLs and crude oil because of market conditions caused by concerns about climate change;

•	conflicts of interest between us, ONEOK Partners, and related parties of ONEOK Partners;

•	the impact of unforeseen changes in interest rates, equity markets, inflation rates, economic recession and other external factors over which we have no control, including the effect on pension and postretirement expense and funding resulting from changes in stock and bond market returns;

•	our indebtedness could make us vulnerable to general adverse economic and industry conditions, limit our ability to borrow additional funds and/or place us at competitive disadvantages compared with our competitors that have less debt, or have other adverse consequences;

•	actions by rating agencies concerning the credit ratings of ONEOK and ONEOK Partners;

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•	the results of administrative proceedings and litigation, regulatory actions, rule changes and receipt of expected clearances involving any local, state or federal regulatory body, including the FERC, the National Transportation Safety Board, the PHMSA, the EPA and CFTC;

•	our ability to access capital at competitive rates or on terms acceptable to us;

•	risks associated with adequate supply to our gathering, processing, fractionation and pipeline facilities, including production declines that outpace new drilling or extended periods of ethane rejection;

•	the risk that material weaknesses or significant deficiencies in our internal controls over financial reporting could emerge or that minor problems could become significant;

•	the impact and outcome of pending and future litigation;

•	the ability to market pipeline capacity on favorable terms, including the effects of:

–	future demand for and prices of natural gas, NGLs and crude oil;

–	competitive conditions in the overall energy market;

–	availability of supplies of Canadian and United States natural gas and crude oil; and

–	availability of additional storage capacity;

•	performance of contractual obligations by our customers, service providers, contractors and shippers;

•	the timely receipt of approval by applicable governmental entities for construction and operation of our pipeline and other projects and required regulatory clearances;

•	our ability to acquire all necessary permits, consents or other approvals in a timely manner, to promptly obtain all necessary materials and supplies required for construction, and to construct gathering, processing, storage, fractionation and transportation facilities without labor or contractor problems;

•	the mechanical integrity of facilities operated;

•	demand for our services in the proximity of our facilities;

•	our ability to control operating costs;

•	acts of nature, sabotage, terrorism or other similar acts that cause damage to our facilities or our suppliers’ or shippers’ facilities;

•	economic climate and growth in the geographic areas in which we do business;

•	the risk of a prolonged slowdown in growth or decline in the United States or international economies, including liquidity risks in United States or foreign credit markets;

•	the impact of recently issued and future accounting updates and other changes in accounting policies;

•	the possibility of future terrorist attacks or the possibility or occurrence of an outbreak of, or changes in, hostilities or changes in the political conditions in the Middle East and elsewhere;

•	the risk of increased costs for insurance premiums, security or other items as a consequence of terrorist attacks;

•	risks associated with pending or possible acquisitions and dispositions, including our ability to finance or integrate any such acquisitions and any regulatory delay or conditions imposed by regulatory bodies in connection with any such acquisitions and dispositions;

•	the impact of uncontracted capacity in our assets being greater or less than expected;

•	the ability to recover operating costs and amounts equivalent to income taxes, costs of property, plant and equipment and regulatory assets in our state and FERC-regulated rates;

•	the composition and quality of the natural gas and NGLs we gather and process in our plants and transport on our pipelines;

•	the efficiency of our plants in processing natural gas and extracting and fractionating NGLs;

•	the impact of potential impairment charges;

•	the risk inherent in the use of information systems in our respective businesses, implementation of new software and hardware, and the impact on the timeliness of information for financial reporting;

•	our ability to control construction costs and completion schedules of our pipelines and other projects; and

•	the risk factors listed in the reports we have filed and may file with the SEC, which are incorporated by reference.

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•	a $0.01 per-gallon change in the composite price of NGLs would change 12-month operating income by approximately $1.8 million for the year ending December 31, 2016, compared with approximately $3.0 million estimated at December 31, 2014 for the year ended December 31, 2015;

•	a $1.00 per-barrel change in the price of crude oil would change 12-month operating income by approximately $1.3 million for the year ending December 31, 2016, compared with approximately $1.6 million estimated at December 31, 2014 for the year ended December 31, 2015; and

•	a $0.10 per-MMBtu change in the price of residue natural gas would change 12-month operating income by approximately $3.3 million for the year ending December 31, 2016, compared with approximately $5.2 million estimated at December 31, 2014 for the year ended December 31, 2015.

•	a $0.01 per-gallon change in the composite price of NGLs would change 12-month operating income by approximately $0.6 million;

•	a $1.00 per-barrel change in the price of crude oil would change 12-month operating income by approximately $0.7 million; and

•	a $0.10 per-MMBtu change in the price of residue natural gas would change 12-month operating income by approximately $0.5 million.

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A.	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

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•	Level 1 - fair value measurements are based on unadjusted quoted prices for identical securities in active markets including NYMEX-settled prices. These balances are comprised predominantly of exchange-traded derivative contracts for natural gas and crude oil.

•	Level 2 - fair value measurements are based on significant observable pricing inputs, such as NYMEX-settled prices for natural gas and crude oil and financial models that utilize implied forward LIBOR yield curves for interest-rate swaps.

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Level 3 - fair value measurements are based on inputs that may include one or more unobservable inputs, including internally developed natural gas basis and NGL price curves that incorporate observable and unobservable market data from broker quotes, third-party pricing services, market volatilities derived from the most recent NYMEX close spot prices and forward LIBOR curves, and adjustments for the credit risk of our counterparties. We corroborate the data on which our fair value estimates are based using our market knowledge of recent transactions, analysis of historical correlations and validation with independent broker quotes. These balances categorized as Level 3 are comprised of derivatives for natural gas and NGLs. We do not believe that our Level 3 fair value estimates have a material impact on our results of operations, as the majority of our derivatives are accounted for as hedges for which ineffectiveness has not been material.

•	Commodity sales - Commodity sales represent the sale of NGLs, condensate and residue natural gas. The commodities are primarily obtained as compensation for or related to providing services. Commodity sales are recognized upon delivery or title transfer to the customer, when revenue recognition criteria are met.

•	Service revenue - Service revenue represents the fees generated from the performance of our services listed above.

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Fee based - Under fee-based arrangements, ONEOK Partners receives a fee or fees for one or more of the following services: gathering, compression, processing, transmission and storage of natural gas; and gathering, transportation, fractionation, exchange and storage of NGLs. The revenue ONEOK Partners earns from these arrangements generally is directly related to the volume of natural gas and NGLs that flow through ONEOK Partners’ systems and facilities, and is not normally directly dependent on commodity prices. However, to the extent a sustained decline in commodity prices results in a decline in volumes, ONEOK Partners’ revenues from these arrangements would be reduced. In

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Percent-of-proceeds - Under POP arrangements in the Natural Gas Gathering and Processing segment, ONEOK Partners gathers and processes natural gas on behalf of producers; sells the resulting residue natural gas, condensate and NGLs at market prices; and remits to producers an agreed-upon percentage of the net proceeds resulting from the sale. The agreed-upon percentage remitted to the producer is reported as cost of sales on the Consolidated Statements of Income. In other cases, instead of remitting cash payments to the producer, ONEOK Partners delivers an agreed-upon percentage of the commodities to the producer (take-in-kind agreements) and sells the volumes ONEOK Partners retains to third parties. Typically, ONEOK Partners’ POP arrangements also include a fee-based component.

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•	established by independent, third-party regulators;

•	designed to recover the specific entity’s costs of providing regulated services; and

•	set at levels that will recover our costs when considering the demand and competition for our services.

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B.	DISCONTINUED OPERATIONS

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D.	FAIR VALUE MEASUREMENTS

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E.	RISK-MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES

•	Futures contracts - Standardized contracts to purchase or sell natural gas and crude oil for future delivery or settlement under the provisions of exchange regulations;

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•	Forward contracts - Nonstandardized commitments between two parties to purchase or sell natural gas, crude oil or NGLs for future physical delivery. These contracts are typically nontransferable and can only be canceled with the consent of both parties; and

•	Swaps - Exchange of one or more payments based on the value of one or more commodities. These instruments transfer the financial risk associated with a future change in value between the counterparties of the transaction, without also conveying ownership interest in the asset or liability.

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F.	PROPERTY, PLANT AND EQUIPMENT

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G.	GOODWILL AND INTANGIBLE ASSETS

H.	SHORT-TERM BORROWINGS

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I.	LONG-TERM DEBT

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J.	EQUITY

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K.	ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)

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L.	EARNINGS PER SHARE

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M.	SHARE-BASED PAYMENTS

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N.	EMPLOYEE BENEFIT PLANS

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O.	INCOME TAXES

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P.	UNCONSOLIDATED AFFILIATES

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Q.	ONEOK PARTNERS

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•	15 percent of amounts distributed in excess of $0.3025 per unit;

•	25 percent of amounts distributed in excess of $0.3575 per unit; and

•	50 percent of amounts distributed in excess of $0.4675 per unit.

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R.	COMMITMENTS AND CONTINGENCIES

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S.	SEGMENTS

•	the Natural Gas Gathering and Processing segment gathers, treats and processes natural gas;

•	the Natural Gas Liquids segment gathers, treats, fractionates and transports NGLs and stores, markets and distributes NGL products; and

•	the Natural Gas Pipelines segment operates regulated interstate and intrastate natural gas transmission pipelines and natural gas storage facilities.

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T.	QUARTERLY FINANCIAL DATA (UNAUDITED)

ITEM 9.	CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND FINANCIAL DISCLOSURE

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ITEM 12.	SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT AND RELATED STOCKHOLDER MATTERS

ITEM 13.	CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS, AND DIRECTOR INDEPENDENCE

ITEM 14.	PRINCIPAL ACCOUNTING FEES AND SERVICES

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