Ad spending is falling off a cliff amid the COVID-19 pandemic — and Facebook and Google, the two heavyweights in digital advertising, are expected to bear the brunt of the downturn in terms of sheer dollars lost.

The two internet giants together could see more than $44 billion in worldwide ad revenue evaporate in 2020, Cowen & Co. analysts estimate. That said, both Google and Facebook will continue to be massively profitable even with double-digit revenue drops.

For 2020, Google total net revenue is now projected to be about $127.5 billion, down $28.6 billion versus Cowen’s prior estimate (an 18% decline). Facebook ad revenue for the year is pegged at $67.8 billion for the year, a drop of $15.7 billion (-19%) vs. Cowen’s previous forecast.

The revised estimates come after Facebook execs disclosed in a blog post Tuesday that the company has “seen a weakening in our ads business in countries taking aggressive actions to reduce the spread of COVID-19.” Facebook’s total usage has increased during the pandemic, with message volume up more than 50% over the last month in countries hit hardest by the virus, but “We don’t monetize many of the services where we’re seeing increased engagement,” Facebook’s Alex Schultz, VP of analytics, and Jay Parikh, VP of engineering wrote.

In 2021, Facebook’s advertising business is projected to “bounce back,” growing 23% year-over-year to $83 billion, the Cowen analyst team led by John Blackledge wrote in a March 25 note.

And while both Facebook and Google are expected to see double-digit declines in profitability, they’re projected to continue to raking in billions on the bottom line: For full-year 2020, Google will generate $54.3 billion in operating income (43% adjusted EBITDA margin) and Facebook will pull in $33.7 billion (49% margin), per Cowen’s forecast.

Regarding coronavirus-fueled ad-spending declines, “digital platforms are feeling the pain soonest, given the relative ease of pulling ad spend versus mediums such as television (who are likely to experience far more pain in Q2 than Q1),” LightShed analyst Rich Greenfield noted in a blog post Wednesday.

Other internet companies that rely on advertising revenue also are expected to get hit by the COVID-19 pandemic. Cowen cut its full-year revenue forecast for Twitter by 18% (to expected revenue of $3.2 billion) while Snap ad sales are expected to be $1.66 billion, 30% lower than Cowen’s previous forecast.

Amazon’s ad business, meanwhile, is “generally less exposed” to the downturn than other large digital platforms because the company’s advertising is mostly related to product searches, Cowen analysts said.

For the overall U.S. ad biz, Cowen & Co. cut revenue estimates by $44 billion for 2020, to $212 billion for the year — down 11% year over year and down 17% versus the firm’s prior forecast (of $256 billion). Industry sectors leading the decline in U.S. ad spending for 2020 are travel, retail and auto, per the report.