But junk funds collapsed a few years ago, and the highest-yielding funds are glutted with the junkiest new issues.

Indeed, now that performance data have been standardized, many people may be tempted to simply invest in the highest-yielding fund.

The highest-yielding fund with assets of at least $100 million was the Kemper Money Market Fund Tax Exempt Portfolio, based in Chicago, yielding 6.88 percent.

The Fidelity Spartan Money Market Fund led the way as the highest-yielding taxable fund, with a yield of 4.42 percent, compared with 4.45 percent a week earlier.

The highest-yielding tax-exempt fund among those with assets greater than $100 million continued to be Strong Municipal Money Market with a yield of 5.01 percent, up from 4.92 the previous week.

Fidelity's Spartan Money Market Fund also led the way as the highest-yielding taxable fund, with a seven-day compound yield of 4.39 percent.

"It may not be the highest-yielding fund, but it's a solid dividend," he said.

The 10 highest-yielding municipal money-market funds reported Friday by Bankrate.com yielded 3.15 percent, on average.

The highest-yielding taxable fund this week was Harbor Money Fund of Toledo, Ohio, which yielded 11.15 percent.

The highest-yielding government-only fund was United Services Government Securities Savings, with a seven-day compounded yield of 3.63 percent.