Now he’s adding foreclosure to the list. “People are moving back down the property ladder,” Mr. Jernigan said.

Bill Martin, a 50-year-old former manager in the technology industry, lost his house in the Southern California community of Lake Forest last August. His local self-storage company sent a truck and driver to pick up his things, a service it offers all new customers.

“Storage has my hopes in it,” said Mr. Martin, who sleeps on a foldout bed in his mother’s guest room. “I don’t tell anyone this, but at least once a week I go over and look at my couch, my refrigerator, my TV stand, my mattress and realize I did have a life, and maybe there’s a way to go back to it.”

Investors agree that hard times for homeowners like Mr. Martin will yield good times for storage firms. U-Store-It’s stock is up 33 percent this year. Extra Space is up 18 percent. Public Storage is up 18 percent.

“People might lose their home but they’re not going to lose their things,” said Charles Ray Wilson of Self Storage Data Services, a research firm.

Yet some evidence suggests that is exactly what is happening. It is impossible to put precise numbers on the phenomenon, partly because the industry is highly fragmented  the majority of facilities are locally owned  and also because the topic is not one the industry cares to dwell on. But auctioneers who dispose of units in default, as well as the bidders who try to buy their contents, say they see increasing signs of strain. They note that more auctions involve people who appear to have had their homes foreclosed.

Image Brook Snyder runs Blair Auctions operation in Chicago. Credit... John Gress for The New York Times

Fred Reger, an auctioneer in Washington and its suburbs, is seeing two trends, which he calls “matching luggage” and “residential units.”