By Chelsey Dulaney

Janus Capital Group Inc., the new home of bond kingpin Bill Gross, said its profit jumped 22% in its fourth quarter, partly driven by higher investment management fee revenue.

The results beat Wall Street estimates.

Mr. Gross, the world's most prominent bond-fund manager, stunned investors and analysts in late September by resigning from Pacific Investment Management Co. to join much-smaller rival Janus. Mr. Gross officially began work as a portfolio manager at Janus on Oct. 6, during the fourth quarter.

Mr. Gross's new bond fund at Janus had net inflows of $176 million in December after raising $1.1 billion in October and November, according to Morningstar.

That money was critical because it helped push the Janus Global Unconstrained Bond fund past $1 billion in assets under management, a key threshold for large investors, according to industry experts.

But The Wall Street Journal reported earlier this month that a majority of the money came from a single Southern California brokerage office--the same office where one of Mr. Gross's personal financial advisers works, according to industry executives who have viewed confidential brokerage data.

Janus said Thursday that it ended the fourth quarter with $183.1 billion in total assets under management, compared with $174.4 billion in the previous quarter and $173.9 billion a year earlier.

Overall, Janus posted a profit of $46.7 million, or 24 cents a share, up from $38.3 million, or 21 cents a share, a year earlier.

Total revenue rose 13% to $254.8 million, driven by higher investment management fees.

Analysts polled by Thomson Reuters had expected 20 cents a share in earnings and $243.8 million in revenue.

Shares were inactive premarket and are up 25% over the past 12 months.

Write to Chelsey Dulaney at Chelsey.Dulaney@wsj.com

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