The parent company of The Los Angeles Times is furloughing 40 employees and cutting the pay of senior managers in an effort to make up for losses brought on by a pandemic-related decline in advertising revenue.

“Due to the unexpected effects of Covid-19, our advertising revenue has nearly been eliminated,” said a memo to the staff on Tuesday from Chris Argentieri, the president of California Times, the publishing company that includes The Times and The San Diego Union-Tribune.

The Times newsroom cheered in 2018 when Patrick Soon-Shiong, a billionaire doctor and entrepreneur, bought The Times and other California publications from what is now Tribune Publishing for $500 million. While The Times has gotten more robust since then, its digital subscription business has been slow, and now the coronavirus has presented a new challenge.

In a separate letter to some staff members on Monday, Mr. Argentieri appeared to be more specific, saying, “The Times has lost more than one-third of its advertising revenue and expects to lose more than half of its advertising revenue in the coming months.”