In what marks the largest outflow activity so far this year, tax-exempt money market funds lost a hefty $5.17 billion and total net assets fell to $306.93 billion for the week ended April 25, according to the Money Fund Report, a service of

The withdrawals by investors followed the exit of $4.70 billion the week before, when total net assets fell to $312.10 billion in a continuing trend of outflows that has lasted for most of the first quarter. The tax-exempt funds lost $2.25 billion and settled with $316.80 billion in the week ended April 11.

The last time tax-exempt money market funds saw net inflows was in the week ended March 21 when they gained a modest $137.8 million and ended with $322.20 billion.

This week, the average seven-day simple yield for the 478 tax-exempt money funds remained at 0.03% for the second week in a row, while the average maturity remained at 26 days.

Meanwhile, the assets of the 1,137 taxable money funds in the report rose by $13.21 billion to $2.397 trillion in the week ended April 26. That amounted to nearly half of the $27.52 billion of outflows the funds suffered in the previous week, which caused total net assets to drop to $2.383 trillion.

The average seven-day simple yield for the taxable funds remained at 0.02% for a fourth consecutive week, while the average maturity declined to 43 days from 45 days the week before.

Overall, the combined assets of the 1,615 money market funds grew by $8.04 billion and finished  the week ended April 26 with $2.704 trillion.

Those total inflows contrasted with $32.22 billion of outflows the week before, which caused the industry’s total net assets to decline to $2.69 trillion.