Assets of the nation's retail money market mutual funds fell $12.88 billion in the latest week to $1.138 trillion.

Assets of taxable money market funds in the retail category fell $9.05 billion to $890.42 billion for the week ended Wednesday, the Washington-based mutual fund trade group said. Tax-exempt fund assets fell $3.83 billion to $247.63 billion.

Assets of institutional money market funds rose $13.08 billion to $2.345 trillion for the same period. Among institutional funds, taxable money market fund assets rose $16.73 billion to $2.169 trillion; assets of tax-exempt funds fell $3.65 billion to $175.12 billion.

The seven-day average yield on money market mutual funds in the week ended Tuesday was 0.06 percent, unchanged from the previous week, said Money Fund Report, a service of iMoneyNet Inc. in Westboro, Mass. The 30-day average yield was also flat at 0.06 percent, according to Money Fund Report.

The seven-day compounded yield was 0.06, the same as the previous week, and the 30-day compounded yield was unchanged at 0.06 percent, Money Fund Report said.

The average maturity of the portfolios held by money funds was 51 days, down from 52 days, said Money Fund.

The online service Bankrate.com said its survey of 100 leading commercial banks, savings and loan associations and savings banks in the nation's 10 largest markets showed the annual percentage yield available on money market accounts rose to 0.33 percent as of Wednesday from 0.32 percent week earlier.

The North Palm Beach, Fla.-based unit of Bankrate Inc. said the annual percentage yield available on interest-bearing checking accounts was unchanged at 0.12 percent from the previous week.

Bankrate.com said the annual percentage yield was 0.63 percent on six-month certificates of deposit, up from 0.62 percent the previous week. Yields were 0.96 percent on 1-year CDs, up from 0.94 percent; 1.40 percent on 2 1/2-year CDs, up from 1.34 percent; and 2.26 percent on 5-year CDs, up from 2.19 percent.

A service of YellowBrix, Inc.