NEW YORK, June 24, 2015 /PRNewswire/ -- S&P Dow Jones Indices will make the following changes to the S&P 500, S&P MidCap 400 and S&P SmallCap 600 indices:

• Columbia Pipeline Group Inc. (NYSE:CPGXwi) will replace Allegheny Technologies Inc. (ATI) in the S&P 500, Allegheny Technologies will replace Unit Corp. (UNT) in the S&P MidCap 400, and Unit Corp. will replace PetroQuest Energy Inc. (PQ) in the S&P SmallCap 600 after the close of trading on Wednesday, July 1. S&P 500 constituent NiSource Inc. (NI) is spinning off Columbia Pipeline Group in a transaction expected to be completed on that date. NiSource will remain in the S&P 500 following the distribution. Allegheny Technologies, Unit and PetroQuest are all ranked near or at the bottom of their current indices.

• S&P SmallCap 600 constituent Casey's General Stores Inc. (CASY) will replace AOL Inc. (AOL) in the S&P MidCap 400, and Nektar Therapeutics (NKTR) will replace Casey's General Stores in the S&P SmallCap 600 after the close of trading on Thursday, June 25. S&P 100 & 500 constituent Verizon Corp. (VZ) acquired AOL in a transaction completed today.

• TopBuild Corp. (NYSE:BLDwi) will replace Aéropostale Inc. (ARO) in the S&P SmallCap 600 after the close of trading on Tuesday, June 30. S&P 500 constituent Masco Inc. (MAS) is spinning off TopBuild in a transaction expected to be completed on that date. Masco will remain in the S&P 500 following the distribution. Aéropostale is ranked near the bottom of the S&P SmallCap 600.

• "New" Gannett Co. Inc. (NYSE:GCIwi) will replace Quiksilver Inc. (ZQK) in the S&P SmallCap 600 after the close of trading on Friday, June 26. S&P 500 constituent Gannett Co. Inc. (GCI) is spinning off "new" Gannett Co. in a transaction expected to be completed on that date. Post spin, the parent company will change its name to TEGNA Inc. and trade under the symbol "TGNA". It will remain in the S&P 500 following the distribution. Quiksilver is ranked near the bottom of the S&P SmallCap 600.

• Cable ONE Inc. (NYSE:CABOwi) will replace Peabody Energy Corp. (BTU) in the S&P MidCap 400 after the close of trading on Tuesday, June 30. S&P MidCap 400 constituent Graham Holdings Company (GHC) is spinning off CableOne in a transaction expected to be completed on that date. Graham Holdings will remain in the S&P MidCap 400 following the distribution. Peabody Energy is ranked near the bottom of the S&P MidCap 400.

• The Chemours Co. (NYSE:CCwi) will replace Semtech Corp. (SMTC) in the S&P MidCap 400, and Semtech will replace Paragon Offshore plc (PGN) in the S&P SmallCap 600 after the close of trading on Tuesday June 30. S&P 100 & 500 constituent E. I. du Pont de Nemours and Co. (DD) is spinning off Chemours in a transaction expected to be completed on that date. Dupont will remain in the S&P 100 & 500 following the distribution. Semtech and Paragon Offshore are ranked near or at the bottom of their current indices.

• "New " Energizer Holdings Inc. (NYSE:ENRwi) will replace Harsco Corp. (HSC) in the S&P MidCap 400, and Harsco will replace FXCM Inc. (FXCM) in the SmallCap 600 after the close of trading on Tuesday, June 30. S&P MidCap 400 constituent Energizer Inc. (ENR) is spinning off "new" Energizer in a transaction expected to be completed on that date. Post spin, the parent company will change its name to Edgewell Personal Care Co. and trade under the symbol "EPC". It will remain in the S&P MidCap 400 following the distribution. Harsco and FXCM are ranked near or at the bottom of their current indices.

Columbia Pipeline Group owns, operates, and develops a portfolio of pipelines, storage, and related midstream assets. Headquartered in Houston, TX, the company will be added to the S&P 500 GICS (Global Industry Classification Standard) Oil & Gas Storage & Transportation Sub-Industry index.

Allegheny Technologies produces and sells specialty materials and components worldwide. Headquartered in Pittsburgh, PA, the company will be added to the S&P MidCap 400 GICS Steel Sub-Industry index.

Unit operates as an oil and natural gas contract drilling company. Headquartered in Tulsa, OK , the company will be added to the S&P SmallCap 600 GICS Oil & Gas Drilling Sub-Industry index.

Casey's General Stores operates convenience stores. Headquartered in Ankeny, IA, the company will be added to the S&P MidCap 400 Food Retail Sub-Industry index.

Nektar Therapeutics is a biopharmaceutical company. Headquartered in San Francisco, CA, the company will be added to the S&P SmallCap 600 Pharmaceuticals Sub-Industry index.

TopBuild installs insulation and other building products. Headquartered in Daytona Beach, FL, the company will be added to the S&P SmallCap 600 Homebuilding Sub-Industry index.

"New" Gannett is a multi-platform news and information company. Headquartered in McLean, VA, the company will be added to the S&P SmallCap 600 Publishing Sub-Industry index.

Cable ONE provides high-speed Internet, cable television, and telephony services. Headquartered in Phoenix, AZ, the company will be added to the S&P MidCap 400 Cable & Satellite Sub-Industry index.

The Chemours Company provides performance chemicals. Headquartered in Wilmington, DE, the company will be added to the S&P MidCap 400 GICS Diversified Chemicals Sub-Industry index.

Semtech designs, develops, manufactures, and markets analog and mixed-signal semiconductor products. Headquartered in Camarillo, CA, the company will be added to the S&P SmallCap 600 Semiconductors Sub-Industry index.

New Energizer Holdings focuses on the manufacture, market, and licensing of household products. Headquartered in St. Louis, MO, the company will be added to the S&P MidCap 400 Household Products Sub-Industry index.

Harsco provides industrial services and engineered products. Headquartered in Camp Hill, PA, the company will be added to the S&P SmallCap 600 Industrial Machinery Sub-Industry index.

Following is a summary of the changes:

Additions to and deletions from S&P  Dow Jones Indices do not in any way reflect an opinion on the investment merits of the companies involved.

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