Assets invested in money market mutual funds grew to S598.23 billion, a gain of 0.9%, in the week ended Sept. 28, the Investment Company Institute reported.
The increase, from $592.7 billion the previous week, was fueled by strong inflows into retail money funds.
These funds closed the week with $428.46 billion of assets, a $3.09 billion gain. Taxable funds held $336.68 billion of the total, up $2.83 billion, while tax-exempt funds totaled $91.78 billion, a $267.7 million increase.
On the institutional side, assets rose $2.44 billion, to $169.78 billion. Though taxable funds for institutional investors reported gains, assets of tax-exempt funds declined.
Taxable institutional funds held $147.54 billion, a rise of $2.51 billion. Tax-exempt funds had $22.24 billion of assets, down $67.8 million in the week.
Money market assets were up 5.2% in the 12 months through September, according to the institute, a Washington-based trade group for mutual fund companies.