NEW YORK (AP) _ Assets in the nation's retail money market mutual funds decreased by $2.14 billion to $808.81 billion, the Investment Company Institute said Thursday.

Assets of taxable money market funds fell by $1.91 billion to $665.96 billion in the retail category for the week ended Wednesday, the Washington-based mutual fund trade group said. Tax-exempt fund assets decreased by $229.7 million to $142.85 billion.

Assets of institutional money market funds increased by $14.86 billion to $565.53 billion for the same period. Among institutional funds, taxable money market fund assets grew by $14.96 billion to $517.75 billion; assets of tax-exempt funds fell by $107.1 million to $47.78 billion.

Total money market assets stood at $1.374 trillion for the week.

Assets for the previous week were revised to $1.362 trillion to reflect reporting errors and a change in the number of funds reporting.

The seven-day average yield on money market mutual funds fell in the week ended Tuesday to 4.50 percent from 4.66 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 fell to 4.63 percent from 4.65 percent, IBC Financial Data said.

The seven-day compounded yield fell to 4.60 percent from 4.77 percent the previous week, while the 30-day compounded yield fell to 4.73 percent from 4.76 percent, IBC Financial Data said.

The average maturity of the portfolios held by money funds was 60 days, unchanged from the previous week, 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 was 2.34 percent as of Wednesday, down from 2.39 percent a week earlier.

The North Palm Beach, Fla.-based newsletter said the annual percentage yield available on interest-bearing checking accounts was 1.07 percent, down from 1.10 percent a week earlier.

Bank Rate Monitor said the annual percentage yield was 4.20 percent on six-month certificates of deposit, down from 4.23 percent the previous week. Yields were 4.31 percent on 1-year CDs, down from 4.35 percent; 4.40 percent on 2 1/2-year CDs, down from 4.43 percent the previous week; and 4.54 percent on 5-year CDs, down from 4.56 percent.