Mortgage companies say troubled borrowers increasingly are signing up.

One of the largest servicers, Bank of America, has mailed out 100,000 deed-in-lieu solicitations to customers in the past 60 days, and its volume of completed transactions is breaking company records, according to officials.

What precisely are deeds-in-lieu? The full name is deeds-in-lieu-of-foreclosure. They are voluntary transfers of property ownership from borrowers to creditors that make court-directed foreclosures unnecessary.

The concept is one of the oldest in real estate, but it got a special boost earlier this year when the Obama administration included it as an option in its Home Affordable Foreclosure Alternatives program, and mortgage giant Fannie Mae cut the penalty-box time for homeowners who use the technique from four years to two before they can qualify for another home mortgage.

Deeds-in-lieu also are surging because they provide a win-win for borrowers and mortgage investors that short sales often cannot match. Tops on the list: speed. Travis Hamel Olsen, chief operating officer of Loan Resolution Corp., a Scottsdale, Ariz., firm that works with lenders to solve troubled borrowers’ problems, said deeds-in-lieu represent “a very expeditious way to move on” for underwater borrowers who are facing potential foreclosure.

“A lot of owners just want to be finished with it, now,” he said. “They don’t want to deal with (the house) anymore.” They don’t want to deal with real estate agents or signs on the front lawn that reveal their financial squeeze to neighbors. They don’t want to haggle with potential buyers coming in with lowball prices. But they also don’t want to simply walk away — strategically default — because that will crater their credit files and scores for as much as seven years.

Greg Hebner, president of the MOS Group Inc. of San Diego, which also works with banks and investors across the country to resolve defaulting borrowers’ situations, said a key motivation now is that lenders are stuck with massive backlogs of underwater homes that haven’t yet gone through foreclosure and been put on the market — the so-called shadow inventory.

Not only is it cheaper for them to do deeds-in-lieu to gain control of those properties, but with current mortgage rates below 5 percent, they’re likely to be able to resell them faster and on potentially more favorable terms in the summer and fall.

“If you can get a lot of inventory moving in the next couple of months” of prime home-buying season, said Hebner, “you are solving a lot of problems.”

Matt Vernon, Bank of America’s top short sale and deed-in-lieu executive, said the technique works so well for both borrowers and mortgage owners that his company is running pilot programs in major housing markets to alert borrowers who might benefit but are not familiar with deeds-in-lieu.

To sweeten the pot, Bank of America is offering cash incentives that range anywhere from $3,000 to $15,000 — and is getting a strong response, according to Vernon.

What are the downsides or limitations of deeds-in-lieu for homeowners?

Probably the most important, say experts, is that they don’t work for every situation involving serious mortgage default. For example, if you have equity in the property, you’ll probably want to pursue a loan modification first, then a short sale, rather than hand your equity stake over to the lender.

Deeds-in-lieu usually don’t work when there are multiple mortgages from different creditors encumbering the property.

Also, though deeds-in-lieu do less damage to borrowers’ credit histories than foreclosures or bankruptcies, they definitely leave a mark.

Fair Isaac, developer of the widely used FICO credit score, says on its “MyFico” Web site that deeds-in-lieu and short sales are both treated as “not paid as agreed” accounts, and are treated the same by the FICO scoring model.