NEW YORK (AP) _ Assets of the nation's retail money market mutual funds decreased by $16.47 billion to $858.49 billion in the latest week, the Investment Company Institute said Thursday.

Assets of taxable money market funds in the retail category decreased by $9.75 billion to $713.17 billion for the week ended Wednesday, the Washington-based mutual fund trade group said. Tax-exempt fund assets decreased by $6.72 billion to $145.32 billion.

Assets of institutional money market funds decreased by $7.55 billion to $576.80 billion for the same period. Among institutional funds, taxable money market fund assets decreased by $7.69 billion to $532.33 billion while assets of tax-exempt funds increased by $134.5 million to $44.47 billion.

Total money market assets stood at $1.435 trillion for the week.

Assets for the previous week were revised to $1.459 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 to 4.28 percent in the week ended Tuesday from 4.30 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 4.32 percent from 4.34 percent, IBC Financial Data said.

The seven-day compounded yield fell to 4.37 percent from 4.40 percent, while the 30-day compounded yield fell to 4.41 percent from 4.43 percent, IBC Financial Data said.

The average maturity of the portfolios held by money funds remained unchanged from the previous week at 61 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 held steady at 2.10 percent as of Wednesday, compared with the previous week.

The North Palm Beach, Fla.-based newsletter said the annual percentage yield available on interest-bearing checking accounts fell to 0.93 percent from 0.94 percent a week earlier.

Bank Rate Monitor said the annual percentage yield rose to 4.13 percent from 4.12 percent on six-month certificates of deposit. The yield fell on 1-year CDs to 4.34 percent from 4.36 percent, while it rose on 2 1/2-year CDs to 4.47 percent from 4.45 percent. The yield also rose on 5-year CDs, to 4.63 percent from 4.61 percent.