The Federal Reserve rate cut that is expected today, whatever size it ultimately takes, has a few noble goals -- lower the cost of borrowing, stimulate the economy, assuage investor fear and entice sidelined funds back into the stock market. It also will have one unintended consequence: Investors will have few options as to where to stash their cash.In their 30-year history, retail money market funds have never "broken the buck," so disregard any alarmists that proclaim if rates go too low the $1.3 trillion in retail money market funds will be in jeopardy of negative returns. In theory, low rates could jeopardize money market investments, but retail investors have nothing to worry about, says Jeff Tjornehoj (pronounced TURN-ahoy), a research analyst at Lipper, a Reuters company. "No one's going to let a negative yield out," he says. "That would haunt them for years. It's paramount to investor trust that a fund company can at least hold onto their cash. If they can't do that, investors would head for the doors and never come back." One place investors might head, regardless, is into bank certificates of deposit. CDs generally offer higher rates than money funds, because they require a specific time commitment. (Investors who pull cash out before the allotted time risk stiff penalties.) But with yields on money funds razor-thin and unlikely to turn around, and CDs seeming more secure, investors may not see the lock-up period as a big sacrifice. Money market funds aren't federally insured the way traditional savings accounts or bank CDs are, but the fund companies that offer them use strong language assuring investors that the value of one share will always be $1. While the net asset value, or NAV, of virtually all money market funds is kept to $1, the interest yield changes daily as managers buy and sell short-term securities that make up these funds. If short-term rates are moving higher, money market fund yields also go higher. Typically, the fund's fees are taken out of the yield.