Hedge-fund manager Solus Alternative Asset Management LP, known for its investment in retail chain Toys “R” Us, told investors this week that it is shutting its flagship fund and will restrict redemptions as it works to sell off holdings, according to a letter viewed by The Wall Street Journal.

Solus is a frequent lender to distressed borrowers, with large holdings in energy companies, and its troubles come as market participants grapple with volatility and forced selling driven by a collapse in oil prices.

The firm in the letter told investors it has received unexpected withdrawal requests this year and that the turbulence caused by the coronavirus has made it difficult to raise cash as it normally would to fulfill those requests by selling holdings.

Investors in Solus have the ability under normal circumstances to withdraw funds on a quarterly basis, but the firm suspended such withdrawals in its flagship fund, according to people familiar with the matter.

Solus gave investors in its flagship fund the option of moving their money into two other funds, which are locked up for two years or more, according to the letter. For those who choose not to move their money into those funds, they will get their money back as quickly as the fund is able to sell off holdings and raise cash.