Setting a record for the second week in a row, money market mutual fund assets climbed 0.4%, to $673.11 billion, in the week that ended May 24.
The run-up, reported by the Investment Company Institute, affected money market funds of all types - taxable and tax-exempt funds for retail and institutional investors.
Retail funds held $473.53 billion, up $2.41 billion in the week. The total includes $379.05 billion in taxable funds and $94.48 billion in tax- exempt funds.
Institutional funds closed the week with $199.58 billion, up $542.1 million. Taxable funds held $175.15 billion; the balance of $24.43 billion was in tax-exempt funds.