WASHINGTON—U.S. manufacturers and other companies that use semiconductors are down to less than five days of inventory for key chips, the Commerce Department said Tuesday, citing the results of a new survey.

In 2019, companies typically maintained 40 days of inventory for key chips, according to the Commerce Department report. Now for the same chips—defined as 160 products that companies identified as being the most challenging to acquire—companies are operating with fewer than five days of inventory, the report said.