Bond mutual funds led the gains, with $1.4 billion in monthly net sales, though this was down from $2.9 billion the previous month.
Balanced mutual funds also enjoyed positive sales, with $1.1 billion gathered in December, down from $357 million in net sales a month prior.
Money-market mutual funds took in $755 million in monthly net sales, down from $1.8 billion, while specialty mutual funds gathered $577 million, down from $1.1 billion in November.
These gains were partially offset by equity mutual funds, which suffered $1.9 billion in net redemptions in December, compared with $744 million in net redemptions the previous month.
“Overall, mutual fund net inflows more than doubled in 2025, with December marking the eighth consecutive month of positive sales,” SIMA said.
At the same time, mutual fund assets were down to $2.53 trillion at the end of December, from $2.54 trillion, marking a $14.7 billion or 0.6% drop from the previous month.
Still, the report highlighted that in 2025, “mutual fund assets increased by $285.8 billion, or [12.7%], despite a modest market-driven decline in December.”
ETFs, meanwhile, recorded both gains in net sales and assets during the final month of 2025, smashing previous records.
They registered $16.9 billion in inflows in December, which the report said was “the highest single-month net sales ever recorded, contributing to 2025 seeing the largest annual inflows in history.”
Equity ETFs dominated the monthly net sales, with $9.7 billion pouring into the funds, up from $6.8 billion the previous month.
Bond ETFs gathered $3.5 billion in net sales, up from $3.2 billion the month before.
Balanced ETFs pulled in $ 1.4 billion, an increase from $1.2 billion in November.
Money-market ETFs collected $1.2 billion in net sales, up from $705 million.
Alongside the positive sales, ETF assets grew to $713 billion by the end of December, from $700 billion the previous month. This represented a $13 billion or 1.9% month-over-month increase.
“ETF assets reached an all-time high at the end of December and increased by $195.5 billion over the year, representing the largest annual dollar increase on record and a one-year growth rate” of 37.8%, the report noted.