TGC Industries to Join Russell 3000 Index

TGC Industries, Inc.

TGC Industries is set to join the broad-market Russell 3000® Index when Russell Investments ("Russell") reconstitutes its comprehensive set of U.S. and global equity indexes on June 26, 2009, according to a preliminary list of additions posted on June 12, 2009 at Inclusion in the Russell 3000 Index indicates that TGC Industries, based upon its total market capitalization, will also automatically be included in the widely followed Russell 2000® Index for U.S. small-cap stocks.

The annual reconstitution of Russell's U.S. indexes captures the 4,000 largest U.S. stocks as of the end of May, ranking them by total market capitalization. Membership in the Russell 3000 Index, which remains in place for one year, means automatic inclusion in either the large-cap Russell 1000® Index or small-cap Russell 2000 Index, as well as 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 Index also serves as the U.S. component of the Russell Global® Index, which Russell launched in 2007. The Russell indexes are widely used by investment managers and institutional investors for index funds and as benchmarks for both passive and active investment strategies. An industry-leading $4 trillion in assets currently are benchmarked to them.