Simon Property Group (NYSE:SPG) is fighting the SARS-CoV-2 coronavirus, and the COVID-19 disease it causes, in its own way -- it's temporarily closing all of its shopping malls in the United States.

The real estate investment trust (REIT), the largest mall operator in the country, announced the move on Wednesday. It said in a tersely worded press release that the closure would take effect at 7 p.m. EDT on that day, and will end on Sunday, March 29.

"The health and safety of our shoppers, retailers and employees is of paramount importance and we are taking this step to help reduce the spread of COVID-19 in our communities," the company wrote.

A Simon Property Group mall in Arizona.

Image source: Simon Property Group

Simon is a veteran in its sector, and has a bulging portfolio of shopping malls and other large retail spaces. As of the end of 2019, the company either owned or held a stake in 204 such properties in the U.S., and 29 in Canada and abroad.

Last month, Simon expanded that footprint with its purchase of an 80% stake in peer retail REIT Taubman Centers (NYSE:TCO). The list of properties owned, managed or leased by Taubman comprises 26 "super-regional" shopping centers, mainly located in the U.S. The purchase price of the all-cash deal amounts to roughly $3.6 billion, which Simon aims to finance with its existing resources. The deal is expected to close in mid-year.

The rampant spread of the coronavirus, and the strict measures many municipalities have taken to bar gatherings of more than small groups of people, have delivered a heavy blow to the retail industry. 

Simon's stock dived by almost 24% on the closure news. That rate is significantly deeper than the declines recorded by major share indexes and many of the market's top stocks.