Position-traded money market funds are a different type of lock-up: Investors must place a trade to get into or out of the fund, which can take a day to complete.

FORBES: Not All Cash Is Created Equal

Sempra can make good money with less risk by backing up a market position on the price of gas with physical supplies of gas coming in through Baja or Cameron.

FORBES: Magazine Article

However, the bank said the significant year-on-year growth in total open interest and the record long position held by the money-managers suggest that the market is overbought and vulnerable to a price break and long liquidation.

FORBES: Speculators Pile Into Gold Futures, Options -- CFTC