Money market mutual fund assets rose $13.55 billion to $3.189 trillion for the week ending Jan. 16, according to the Investment Company Institute.
Retail money market mutual fund assets rose $11.84 billion to $1.184 trillion, and assets of taxable money market funds rose $10.73 billion to $893.79 billion.
Tax-exempt fund assets rose by $1.11 billion to $2.90.47 billion.
The seven-day average yield on money market mutual funds fell 3.96% from 3.99%, according to Money Fund Report, a service of iMoneyNet Inc. The 30-day average yield fell to 3.98% from 4.01%.
This week, more than any that we've seen since yields started to move south last summer, showed the biggest one-week change, said Greg McBride, a senior financial analyst at Bankrate.com. The outlook is for yields to continue moving lower in the coming months.
The seven-day compounded yield fell from 4.07% to 4.04%, and the 30-day compounded yield fell from 4.09% the previous week to 4.06%.
Assets of institutional money market funds rose $1.72 billion to $2.005 trillion.