Pimco's flagship Total Return bond fund added money in December, the first month of inflows since before the sudden departure of co-founder Bill Gross in September 2014.

The fund attracted net inflows of $1.3 billion during the final month of the year, helped by capital-gains distributions, Pimco said Tuesday. The fund ended the year with $89.9 billion in assets. It isn't clear whether the fund would have posted net outflows excluding the distribution.