“The mall has been losing ground for a long time, now it’s losing ground faster,” said Jan Kniffen, a current retail consultant and former exec at The May Department Stores, which was folded into Macy’s.

A third of America’s malls are going to shut permanently by 2021, according to one former department store executive, as their demise is accelerated due to the coronavirus pandemic.

“The mall has been losing ground for a long time, now it’s losing ground faster,” said Jan Kniffen, a current retail consultant and former exec at The May Department Stores, which was eventually folded into Macy’s.

“I expect we are going to see at least 20% of the [inside of the] mall go. I expect to see a third of the malls go a lot sooner than we thought,” he said Wednesday on CNBC’s “Squawk Box.”

Initially, he was expecting roughly 33% of America’s malls to go dark by 2030. Now, Kniffen thinks that will happen by next year.

There are still about 1,000 malls operating in the U.S. today, according to commercial real estate services firm Green Street Advisors.

A large majority of those malls are classified as so-called B- C- and D-rated malls, meaning they bring in fewer sales per square foot than an A mall. An A++ mall could bring in as much as $1,000 in sales per square foot, for example, while a C+ mall does about $320.

Per Green Street’s analysis, there are roughly 380 C- and D-rated malls out of the 1,000. And those are considered the most at risk of going dark, permanently, as they don’t generate enough sales to maintain the property and have greater vacancy rates. Green Street has said C malls “are not viable retail centers long term.”