Citadel's flagship fund Wellington was up 1.3% in April, as it navigated a tumultuous month, a source familiar with the matter said Thursday.

Other Citadel funds also posted positive performances last month. The tactical trading fund rose 1.9%, while the global equities fund gained 2.2%, and the global fixed income fund rose 1.2%.

For the year through April, the Wellington fund is up 0.5%.

The Wall Street Journal first reported on Citadel's funds performance.

Citadel founder Ken Griffin at a conference last week, when asked about President Donald Trump's new trade policy and the president's cricism of Federal Reserve Chair Jerome Powell, warned about potential damage to the creditworthiness of U.S. Treasuries and how the "U.S. brand" could be hurt.

"We put that brand at risk," he said. "The president, the secretary of Treasury and the secretary of commerce need to be very thoughtful that when you have a brand you need to behave in a way that respects that brand, that strengthens that brand, because when you tarnish that brand, it can be a lifetime to repair the damage that has been done."

Citadel declined to comment on the firm's performance.