The severity of the pandemic-caused ad market slump is becoming clearer. The immediate impact is particularly sharp for digital media, where some executives report declines of as much as 50% in ad bookings. But analysts also predict that big companies like Alphabet, Facebook and Twitter will be hurt—and that they could feel the damage for several years.

Ad platforms like Facebook and Google will lose $50 billion in ad revenue cumulatively over the next four years in the U.S. from small and medium-size businesses going out of business as a result of the pandemic lockdowns, estimates Standard Media Index, which tracks advertising trends. That amount translates to about 10% of the two giants’ combined U.S. annual ad revenues. It’s going to take years for the ad market to recover, said James Fennessey, CEO of Standard Media Index.