FILE PHOTO: William 'Bill' Ackman, CEO and Portfolio Manager of Pershing Square Capital Management, speaks during the Sohn Investment Conference in New York City, U.S., May 8, 2017. REUTERS/Brendan McDermid/File Photo

BOSTON (Reuters) - Billionaire hedge fund investor William Ackman on Tuesday said he has moved to protect the firm’s $6.6 billion portfolio, which includes restaurant chain and hotel stocks, as the spread of the coronavirus has sparked prolonged panic selling in markets.

Ackman said he expects the outbreak, which has been detected in roughly 80 countries, to weigh on growth in the United States and abroad and affect both stock and credit markets.

Over the last 10 days, “we have taken steps to protect the portfolio from downward market volatility,” wrote Ackman, who oversees Pershing Square Capital Management. He declined to say exactly what steps he took.

Ackman spoke out on the same day that the Federal Reserve announced an emergency interest rate cut. Ackman’s statement, an unusual move for someone who seldom discusses portfolio movements publicly, underscores investors’ fears that the coronavirus will have serious implications for economic growth.

“We believe that efforts to contain the coronavirus are likely to have a substantial negative impact on the U.S. and global economies, and on equity and credit markets,” the statement said.

Ackman said hedging was preferable to selling off his portfolio of companies whose businesses are otherwise strong and include Chipotle Mexican Grill CMG.N, Hilton Worldwide HLT.N, home improvement chain Lowe's LOW.N, Burger King operator Restaurant Brands International QSR.TO and Berkshire Hathaway BRKa.N, among others. The hedge fund sold out of its position in Starbucks SBUX.O earlier in the year.

In the first two months of the year, the firm’s Pershing Square Holdings portfolio fell 7.1%, after having gained 58.1% last year, which made it one of the industry’s best-performing hedge funds. The market drop has taken a bite out of the size of Ackman’s funds, according to a report which put assets under management at $6.6 billion at the end of February compared with $7.5 billion at the end of December.