Alliant Energy is a public utility holding company, engaged in providing regulated electric and natural gas service. The company's subsidiaries are: Interstate Power and Light Company, which is engaged principally in the generation and distribution of electricity and the distribution and transportation of natural gas to retail customers in select markets in Iowa; Wisconsin Power and Light Company, which is engaged principally in the generation and distribution of electricity and the distribution and transportation of natural gas to retail customers in select markets in Wisconsin; and Alliant Energy Finance, LLC, which manages a portfolio of wholly-owned subsidiaries and additional holdings.

Ameren is a public utility holding company. Through its subsidiary, Union Electric Company, the company operates a rate-regulated electric generation, transmission, and distribution business and a rate-regulated natural gas distribution business in Missouri. Through its subsidiary, Ameren Illinois Company, the company operates rate-regulated electric transmission, electric distribution, and natural gas distribution businesses in Illinois. Through its Ameren Transmission Company of Illinois subsidiary, the company operates a Federal Energy Regulatory Commission rate-regulated electric transmission business. The company also has other subsidiaries that conduct other activities, such as providing shared services.

Atmos Energy is engaged in the regulated natural gas distribution and pipeline and storage businesses. The company delivers natural gas through regulated sales and transportation arrangements to residential, commercial, public-authority and industrial customers. The company's segments are: Distribution, which is comprised of its regulated natural gas distribution and related sales operations; and Pipeline and Storage, which consists of the pipeline and storage operations of its Atmos Pipeline-Texas Division (APT) and its natural gas transmission operations in Louisiana. APT has intrastate pipeline operations in Texas with a focus on the natural gas-producing areas of central, northern and eastern Texas.

CMS Energy is a holding company. The company has several subsidiaries, including: Consumers Energy Company, an electric and gas utility that serves individuals and businesses operating in the alternative energy, automotive, chemical, food, and metal products industries, as well as a group of other industries; CMS Enterprises Company, through its subsidiaries and equity investments, is engaged in domestic independent power production, including the development and operation of renewable generation, and the marketing of independent power production; and EnerBank USA, an industrial bank located in Utah that provides unsecured consumer installment loans, primarily for financing home improvements.

Consolidated Edison is a holding company. Through its subsidiaries, the company is engaged in provision of energy services. The company's subsidiaries include: Consolidated Edison Company of New York, Inc.'s principal business operations are its regulated electric, gas and steam delivery businesses; Orange & Rockland Utilities, Inc.'s principal business operations are its regulated electric and gas delivery businesses; Con Edison Clean Energy Businesses, Inc. develops, owns and operates renewable and energy infrastructure projects and provides energy-related products and services to wholesale and retail customers; and Con Edison Transmission, Inc. invests in electric and gas transmission projects.

DTE Energy is a holding company. The company is engaged in the generation, purchase, distribution and sale of electricity to customers in southeastern Michigan through its DTE Electric Company subsidiary, as well as in the purchase, storage, transportation, distribution and sale of natural gas throughout Michigan and the sale of storage and transportation capacity through its DTE Gas Company subsidiary. The company's non-utility operations are: gas storage and pipelines, which consists of natural gas pipeline, gathering, transportation, and storage businesses; power and industrial projects; and energy trading, which consists of energy marketing and trading operations.

Duke Energy is a holding company. Through its subsidiaries, the company operates as an energy company. The company's segments include: Electric Utilities and Infrastructure, which provides retail electric service through the generation, transmission, distribution and sale of electricity to customers within the Southeast and Midwest regions of the United States; Gas Utilities and Infrastructure, which conducts natural gas operations, as well as owns, operates and has investments in various pipeline transmission and natural gas storage facilities; and Commercial Renewables, which acquires, develops, builds, operates and owns wind and solar renewable generation throughout the continental United States.

Entergy is a holding company. Through its subsidiaries, the company is an integrated energy company engaged mainly in electric power production and retail distribution operations. The company owns and operates power plants. The company has two segments: Utility, which generates, transmits, distributes and sells electric power to retail and wholesale customers in Arkansas, Louisiana, Mississippi, and Texas; and Entergy Wholesale Commodities, which includes the ownership, operation, and decommissioning of nuclear power plants, located in the northern United States, the sale of the electric power produced by its operating plants to wholesale customers, and also provides services to other nuclear power plant owners.

Eversource Energy is a public utility holding company. Through its subsidiaries, the company has four segments: electric distribution, which is engaged in the distribution of electricity to retail customers in Connecticut, Massachusetts and New Hampshire; electric transmission, which owns and maintains transmission facilities that are part of an interstate power transmission grid over which electricity is transmitted throughout New England; natural gas distribution, which distributes natural gas to communities in Massachusetts and cities and towns in Connecticut; and water distribution, which provides water services in towns and cities in Connecticut, Massachusetts and New Hampshire.

Fortis is principally an international electric and gas utility holding company. Co. also holds investments in non-regulated generation assets. Co.'s business segments are: Regulated Electric & Gas Utilities - United States; Regulated Gas Utility - Canadian; Regulated Electric Utilities - Canadian; Regulated Electric Utilities - Caribbean; Non-Regulated - Fortis Generation; Non-regulated - Non-Utility; and Corporate and Other. Its regulated utilities served more than 3.0 million customers across Canada and in New York State and the Caribbean. Co. also holds investments in non-regulated generation assets in Canada and Belize, through Fortis Generation.

MDU Resources Group is a holding company. Through its subsidiaries, the company is organized into five reportable business segments: electric, which generates, transmits and distributes electricity in Montana, North Dakota, South Dakota and Wyoming; natural gas distribution, which distributes natural gas in Montana, North Dakota, South Dakota, Wyoming, Idaho, Minnesota, Oregon and Washington; pipeline and midstream, which provides natural gas transportation, underground storage and gathering services; construction materials and contracting, which mines, processes and sells construction aggregates; and construction services, which provides inside and outside specialty contracting services.

NextEra Energy is a holding company, engaged in electric power and energy infrastructure. The company has two principal businesses, Florida Power & Light Company (FPL) and NextEra Energy Resources, LLC (NEER). FPL is a rate-regulated electric utility engaged primarily in the generation, transmission, distribution and sale of electric energy in Florida. FPL provides service to its electric customers through a transmission and distribution system that links its generation facilities to its customers. NEER, through its subsidiaries, owns, develops, constructs, manages and operates electric generation facilities in wholesale energy markets primarily in the United States and Canada.

Oneok is a midstream service provider. The company's segments include: Natural Gas Gathering and Processing, which provides midstream services to producers in North Dakota, Montana, Wyoming, Kansas and Oklahoma; natural gas liquids (NGLs), which owns and operates facilities that gather, fractionate, treat and distribute NGLs and store NGL products, primarily in Oklahoma, Kansas, Texas, New Mexico and the Rocky Mountain region; and Natural Gas Pipelines, which provides transportation and storage services to end users through its wholly owned assets and its ownership interests in Northern Border Pipeline Company and Roadrunner Gas Transmission, LLC.

PPL is a utility holding company. Through its regulated utility subsidiaries, the company delivers electricity to customers in United Kingdom, Pennsylvania, Kentucky, and Virginia; delivers natural gas to customers in Kentucky; and generates electricity from power plants in Kentucky. The company's segments are: United Kingdom Regulated, which has regulated electricity distribution operations in United Kingdom; Kentucky Regulated, which is engaged in the regulated generation, transmission, distribution and sale of electricity in Kentucky and Virginia, and the distribution and sale of natural gas in Kentucky; and Pennsylvania Regulated, which delivers electricity in eastern and central Pennsylvania.

Public Service Enterprise Group, through its subsidiaries, is engaged in the energy industry. The company conducts its business through two subsidiaries, Public Service Electric and Gas Company (PSE&G) and PSEG Power LLC (PSEG Power). PSE&G is a public utility, which is engaged in the transmission of electricity and distribution of electricity and natural gas in certain areas of New Jersey; and PSEG Power is a multi-regional energy supply company that integrates the operations of its merchant nuclear and fossil generating assets with its power marketing businesses and fuel supply functions through energy sales in energy markets primarily in the Northeast and Mid-Atlantic United States.

Sempra Energy is an energy-services holding company. The company's segments are: San Diego Gas & Electric Company, which provides electric services and natural gas services in Southern California; Southern California Gas Company, which owns and operates a natural gas distribution, transmission and storage system that supplies natural gas in Southern California and portions of central California; Sempra Texas Utilities, which includes Oncor Electric Delivery Company LLC that provides electricity to consumers; Sempra Mexico, which develops, owns and operates, or holds interests in, energy infrastructure in Mexico; and Sempra LNG, which develops projects for the export of liquefied natural gas.

Xcel Energy is a regulated electric and natural gas delivery company which serves customers in mid-western and western states, including portions of Colorado, Michigan, Minnesota, New Mexico, North Dakota, South Dakota, Texas and Wisconsin. The company's reportable segments include: regulated electric utility, which generates, transmits and distributes electricity in Minnesota, Wisconsin, Michigan, North Dakota, South Dakota, Colorado, Texas and New Mexico; regulated natural gas utility, which transports, stores and distributes natural gas primarily in portions of Minnesota, Wisconsin, North Dakota, Michigan and Colorado; and other, which includes steam revenue and appliance repair services.