Citadel's flagship Wellington Fund is up 10% so far this year, a source familiar with the returns told CNBC on Tuesday.
The fund was up 3.33% in April, driven by equities, commodities, credit, and quant strategies.
The Tactical Trading fund at the firm is up 3.03% for the month and 8.54% for the year, while Citadel Global Equities is up 2.61% in April and 5.62% so far this year.
Citadel manages more than $30 billion and is run by billionaire Ken Griffin. The S&P 500 was up 3.93% in April and is up more than 15% year to date.