NEW YORK (AP) _ Assets of the nation's 660 retail money market mutual funds fell by $3.10 billion in the latest week to $562.23 billion, the Investment Company Institute said Thursday.

Assets of the 404 taxable money market funds in the retail category fell by $1.82 billion to $458.15 billion for the week ended Wednesday, the Washington-based mutual fund trade group said. The 256 tax-exempt fund assets fell by $1.28 billion to $104.07 billion.

Assets of the 299 institutional money market funds rose by $3.46 billion to $252.74 billion for the same period. Among institutional funds, the 237 taxable money market fund assets rose by $3.38 billion to $xxx.xx billion; assets of the 62 tax-exempt funds rose by $79.6 million to $27.75 billion.

Total money market assets stood at $814.96 billion for the week.

Assets for the previous week were revised to $814.60 billion to reflect reporting errors and a change in the number of funds reporting.

The seven-day average yield on money market mutual funds rose in the week ended Tuesday to 4.78 percent from 4.77 percent the previous week, said IBC's Money Fund Report, a trade journal published in Ashland, Mass., by IBC Financial Data Inc. The 30-day average yield rose to 4.76 percent from 4.75 percent, IBC Financial Data said.

The seven-day compounded yield rose to 4.89 percent from 4.88 percent the previous week, and the 30-day compounded yield rose to 4.88 percent from 4.87 percent, IBC Financial Data said.

The average maturity of the portfolios held by money funds was 52 days, down from 53 days, IBC Financial Data said.

The newsletter Bank Rate Monitor 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 remained unchanged at 2.66 percent as of Wednesday from a week earlier.

The North Palm Beach, Fla.-based newsletter said the annual percentage yield available on interest-bearing checking accounts remained unchanged from the previous week at 1.41 percent.

Bank Rate Monitor said the annual percentage yield was 4.64 percent on six-month certificates of deposit, up from 4.63 percent the previous week. Yields were 4.98 percent on 1-year CDs, up from 4.97 percent; 5.19 percent on 2 1/2-year CDs, down from 5.20 percent; and 5.57 percent on 5-year CDs, up from 5.56 percent.