Credo Petroleum Corporation to Join the Russell 3000(R) Index

DENVER, June 19, 2012 (GLOBE NEWSWIRE) -- Credo Petroleum Corporation CRED, an oil and gas exploration and production company with significant assets in the North Dakota Bakken and Three Forks, Kansas, Nebraska, the Texas Panhandle and Oklahoma, today announced that the Company is set to join the Russell 2000® Index and Russell 3000® Index when Russell Investments reconstitutes its comprehensive set of U.S. and global equity indexes at the market close on June 22, 2012 as confirmed by the preliminary list of additions posted on www.russell.com.

The Russell 2000® Index is a subset of the Russell 3000® Index. The annual reconstitution of the Russell 3000 captures the 3,000 largest U.S. stocks as of the end of May, ranking them by total market capitalization. The largest 1,000 companies in this ranking comprise the Russell 1000 and the next 2,000 companies become the Russell 2000. Membership in the Russell 3000 remains in place for one year and also means automatic inclusion in the appropriate growth and value style indexes.  Russell determines membership for its equity indexes primarily by objective, market-capitalization rankings and style attributes.

The Russell 3000 also serves as the U.S. component to the Russell Global Index, which Russell launched in 2007.

Russell indexes are widely used by investment managers and institutional investors for index funds and as benchmarks for investment strategies. According to Russell Investment Group, institutional investment professionals currently responsible for over $3.9 trillion in assets use Russell indexes to guide their portfolios.

About Russell

Russell Investments (Russell) is a global asset manager and one of only a few firms that offers actively managed, multi-asset portfolios and services that include advice, investments and implementation.  Working with institutional investors, financial advisors and individuals, Russell's core capabilities extend across capital markets insights, manager research, Indexes, portfolio implementation and portfolio construction.

About Credo Petroleum

Credo Petroleum Corporation is an independent oil and gas exploration and production company based in Denver, Colorado. The Company has significant operations in the Williston Basin of North Dakota, Kansas, Nebraska, the Anadarko Basin of the Texas Panhandle and northwest Oklahoma, and in southern Oklahoma. Credo uses advanced technologies to systematically explore for oil and gas and, through its patented Calliope Gas Recovery System, to recover stranded reserves from depleted gas reservoirs. For more information, please visit our website at www.credopetroleum.com or contact us at 303-297-2200.

This press release includes certain statements that may be deemed to be "forward-looking statements" within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. All statements included in this press release, other than statements of historical facts, address matters that the Company reasonably expects, believes or anticipates will or may occur in the future. Such statements are subject to various assumptions, risks and uncertainties, many of which are beyond the control of the Company. Investors are cautioned that any such statements are not guarantees of future performance and that actual results or developments may differ materially from those described in the forward-looking statements. Investors are encouraged to read the "Forward-Looking Statements" and "Risk Factors" sections included in the Company's Annual Report on Form 10-K/A for more information. Although the Company may from time to time voluntarily update its prior forward looking statements, it disclaims any commitment to do so except as required by securities laws.