T. Lynne Pixley for The New York Times

Zillow.com is adding a new sort of property to its real estate Web site: homes that are bank-owned or are in the foreclosure process but aren’t officially listed for sale.

Having access to an inventory of “presale” properties — those that are pending foreclosure or that have already been foreclosed on — may make it easier to get a jump on properties potential buyers are interested in, said Amy Bohutinsky, Zillow’s chief marketing officer.

Even as the housing market has rebounded, many buyers remain reluctant to put their homes on the market, creating inventory shortages in some housing markets. But millions of homes are about to come on the market for various reasons, Ms. Bohutinsky said, either because the owner has fallen behind on mortgage payments and has been served with a foreclosure notice or the bank has foreclosed but hasn’t put the property on the market yet.

Zillow has gleaned such information on about 1.8 million properties from public records, and is making it available free — unlike sites for investors, which have traditionally charged a fee. The inventory includes more than 1.5 million properties where the lender has started foreclosure proceedings or an auction has been scheduled, and 250,000 foreclosed properties that aren’t yet listed for sale.

“The opportunity this represents for buyers is, they could make an offer to the owners or to the bank to buy the home,” she said. “Or they could set up alerts to see when it does come on the market.”

Even if you’re not interested in making an offer on a foreclosed property, Ms. Bohutinsky said, it can help to decide on an offer for a home that is listed for sale. If you know that several homes nearby are in foreclosure, you can adjust your offer price accordingly.

Buying homes in foreclosure has traditionally been the realm of investors who are prepared to handle a potentially daunting, complex process. Banks don’t necessarily want to sell to buyers who need a mortgage, but prefer investors who can pay cash. Ron Lieber, the paper’s Your Money columnist, has written in detail about the challenges of buying a bank-owned home. Proceedings can sometimes be adversarial, since the previous owner usually didn’t want to part with the home.

To address that problem, Zillow can also put consumers in touch with local agents who specialize in foreclosures. (The agents pay Zillow a fee to be listed on the site.) The site has also added a foreclosure primer.

“It’s important for the buyer to work with an agent who knows what they’re doing,”she said.

Would you consider making an offer on a foreclosed property? Why or why not?