The market selloff is creating enough bargains for investors to begin buying, though it’s too soon to call the bottom, according to Howard Marks, co-founder of distressed investment specialist Oaktree Capital Management.

“We’re certainly buying,” Marks said in a Bloomberg Television interview on Friday. “If you’re a distressed investor, you must turn more aggressive when you’re given good chances. I’m not saying this is the bottom, but this is certainly a time to do some buying.”

Stocks plunged and U.S. credit markets were suffering their worst day in a decade as fears intensify that the spreading coronavirus will hurt corporate income and some companies’ ability to repay debt. The scale of the crisis depends on how long it lasts, according to Marks, who cited forecasts of as long as 18 months to develop a vaccine.

“If it goes 18 months, we’re going to have a serious event here,” Marks said.

Oaktree is one of the largest distressed-debt investors in the world, with about $20 billion committed to credit from faltering companies. The fund has thrived most in times of economic stress, when prices on bonds of companies in danger of defaulting fall to deep discounts.

The current threat to markets differs from the 2008 financial crisis, Marks said on Friday, because it’s caused by exogenous factors rather than company behavior or economic imbalances.

“This one is I think is particularly terrifying to most people,” he said. “Pandemic, that’s a scary word.”

Historically, a good time to buy has been when high-yield spreads widen to at least 500 basis points, or 5 percentage points, above Treasuries, Marks said. “We are starting to get to the point where we can have good outcomes.”