Feb. 1 (Bloomberg) -- U.S. equity options volume fell to 337.2 million contracts in January, down 12 percent from a year earlier, according to data compiled by Chicago-based OCC.

The following table gives market-share figures for each U.S. venue based on contracts linked to stocks, exchange-traded funds and indexes.

Notes:

--CBOE Holdings Inc. owns the Chicago Board Options Exchange and C2, which started in October 2010. The two exchanges handled a total of 26.94 percent of U.S. equity options trading last month.

--Nasdaq OMX Group Inc. owns Nasdaq OMX PHLX and Nasdaq Options Market. The two exchanges handled a total of 25.59 percent of U.S. equity options trading last month.

--NYSE Euronext owns NYSE Amex and NYSE Arca. The two exchanges handled a total of 24.95 percent of U.S. equity options trading last month.

--Eurex, which is controlled equally by Deutsche Boerse AG and SIX Swiss Exchange Ltd., owns the International Securities Exchange.

--Bats Global Markets owns Bats Options, which started in February 2010.

--TMX Group Inc. owns 53.8 percent of the Boston Options Exchange. The rest is controlled by Citadel LLC, Citigroup Inc., Credit Suisse Group AG, Interactive Brokers Group Inc., JPMorgan Chase & Co., Morgan Stanley and UBS AG.

--Editor: Joanna Ossinger

To contact the reporters on this story: Jennifer Prince in New York at jprince10@bloomberg.net; Jeff Kearns in New York at jkearns3@bloomberg.net

To contact the editors responsible for this story: Nick Baker at nbaker7@bloomberg.net; Laurie Meisler at lmeisler@bloomberg.net