break the buck
v. phr.β Β«He thinks itβs unlikely the companies running money market funds would allow them to “break the buck,” as itβs known in Wall Street parlance even if the funds lost money on SIV-related investments. The draw of money market funds, of course, is that an investor putting in $1 get $1 back plus interest. If a fund were to, say, give back only 90 cents for every dollar, investors would be outraged.Β» ββMoney Market Investors Face Latest Worry” by Tim Paradis Forbes Oct. 23, 2007. (source: Double-Tongued Dictionary)