After garnering over $1 billion that ended a nearly month-long, outflow pattern last week, tax-exempt money market funds were back in negative territory this week as they lost $449.9 million and total net assets settled at $269.80 billion for the week ended Sept. 17, according to The Money Fund Report, a service of iMoneyNet.com.

The arrival of $1.94 billion last week -- which caused total net assets increase to $270.25 billion, was the first inflow activity since a modest $124.8 million saw total net asset rise to $272.46 billion in the week ended Aug. 20.

Meanwhile, back to this week, the average seven-day simple yield for the 438 reporting tax-exempt money funds remained at 0.01% for the 16th consecutive week, while the average maturity was unchanged at 38 days.

In the taxable arena, on the other hand, the total net assets of the 1,063 reporting funds lost $10.89 billion, which caused a decline in total net assets to $2.277 trillion in the week ended Sept. 18. That was in contrast to the prior week when total net assets settled at $2.288 trillion after the arrival of $17.73 billion of inflows.

The average seven-day simple yield for the taxable funds stayed at 0.03% for the second week in a row, while the average maturity increased by one day to 47 days compared to last week.

Overall, the combined assets of the 1,501 reporting money funds lost $11.34 billion as total net assets finished at $2.547 trillion for the week ended Sept. 18, according to the report. That was on the heels of $19.67 billion of inflows in the previous week when total net assets settled at $2.559 trillion.