Total U.S. money market mutual fund assets fell by $14.78 billion to $2.567 trillion for the week that ended Wednesday, the Investment Company Institute said Thursday.

Assets of the nation’s retail money market mutual funds fell $1.86 billion to $890.79 billion, the Washington-based mutual fund trade group said. Assets of taxable money market funds in the retail category fell $1.85 billion to $703.24 billion. Tax-exempt retail fund assets fell $10 million to $187.55 billion.

The North Palm Beach, Fla.-based unit of Bankrate Inc. said the annual percentage yield available on interest-bearing checking accounts was unchanged from the week before at 0.06 percent.

Bankrate.com said the annual percentage yield on six-month certificates of deposit was unchanged from the previous week at 0.22 percent. The yield on one-year CDs was also unchanged at 0.33 percent. It rose to 0.53 percent from 0.52 percent on two-and-a-half-year CDs. It was flat at 1.13 percent on five-year CDs.

Meanwhile, assets of institutional money market funds fell $12.92 billion to $1.677 trillion. Among institutional funds, taxable money market fund assets fell $14.05 billion to $1.589 trillion; assets of tax-exempt funds rose $1.14 billion to $88.04 billion.

The seven-day average yield on money market mutual funds was 0.03 percent in the week that ended Tuesday, unchanged from the previous week, said Money Fund Report, a service of iMoneyNet Inc. in Westborough, Mass.

The average maturity of portfolios held by money market mutual funds fell to 45 days from 46 days in the previous week.