(Adds Bodman comments, background on margins)

WASHINGTON, May 23 (Reuters) - Significantly raising margin requirements on oil futures trading at the New York Mercantile Exchange NMX.N would not rein in speculative investors and bring down crude prices, U.S. Energy Secretary Sam Bodman said on Friday.

Many U.S. lawmakers blame hedge funds, pension fund managers and other speculative investors for pushing up prices for crude oil and other commodities to record levels.

“I don’t think that the margin requirements per se are going to have any impact on it,” Bodman said in an interview on CNBC television.

Legislation is pending in the U.S. Senate that would require the Commodity Futures Trading Commission, which regulates NYMEX, to significantly raise the amount of money, or margin, that speculators have to put up to trade oil futures.

The bill does not specify how high margins should be increased, leaving it up to the CFTC to decide.

However, the CFTC has told Congress that, while more speculators are doing business in the futures markets, the agency has no evidence they have caused prices to rise.

When purchasing stocks, many brokerage firms require investors to have between 30 percent and 40 percent of the market value of the securities in margin accounts.

Margin requirements for futures are generally lower, less than 10 percent for many contracts, and often change depending on the volatility of the contracts.

Separately, Bodman said he supported broadening some regulatory powers of the CFTC, which this week was given new authority from Congress to monitor and collect more information on some of the energy trading going on in exempt commercial markets, such as the Intercontinental Exchange ICE.N. (Reporting by Tom Doggett; Editing by Walter Bagley)