LOS ANGELES — Countrywide Financial Corp. lost $1.2 billion in the third quarter, but its shares soared today after the nation’s largest mortgage lender said it expects to be profitable this quarter and next year.

It was Countrywide’s first quarterly loss in 25 years.

But the Calabasas, Calif.-based company said it will be profitable in the fourth quarter and in 2008, as it restructures its business to take advantage of the current market.

Shares jumped $2.18, or 16.6%, to $15.25 in midday trading after initially rising as high as $16.30. The stock has ranged $12.07 and $45.26 the past 52 weeks.

The loss for the third-quarter came as mortgage market woes forced Countrywide to set aside millions in loan-loss provisions and writedowns, and the lender originated fewer loans.

Countrywide’s loss amounted to $2.85 a share for the July-September period compared with a profit of $647.6 million, or $1.03 a share, a year ago.

Analysts polled by Thomson Financial, on average, forecast a loss of $1.28 a share for the quarter.

Countrywide reported a revenue figure of negative $50 million in the third quarter because of the impact of impairments and charges, versus $2.82 billion during the same period a year ago.

Countrywide’s chairman and chief executive, Angelo Mozilo, attributed the quarterly loss on “unprecedented disruptions” in the mortgage market and the ongoing national housing slump.

The executive sought to reassure investors, however, noting steps the company has taken to secure financing, tighten underwriting standards, and shift its mortgage lending business into its banking subsidiary, Countrywide Bank.

An analyst with Stifel Nicolaus & Co. Inc., Chris Brendler, said he is not convinced the company will turn a profit next quarter.

“They seem to have taken some big write-downs, taken a lot pain this quarter, the pain going forward should be smaller,” Mr. Brendler said. “I still remain concerned about the potential for another credit write-down and just how profitable this business will be, even after they get past the credit headaches in the near term.”

Origination volume fell to $96 billion, from $118 billion as Countrywide shifted its product mix to more traditional loans.

Countrywide ramped up its loan-loss reserves to fight rising delinquencies and defaults, especially among subprime mortgages given to customers with poor credit history. Countrywide reserved $934 million for bad loans in the third quarter, up from $38 million held during the same quarter last year.

The lender moved about $12 billion in nonconforming loans to its held-for-investment portfolio after having to take a write-down on them.

Some 4.41% of Countrywide’s conventional first mortgage loans were delinquent as of September 30, up from 2.57% in the year-ago quarter. For prime home-equity loans, delinquencies inched up to 13.5% compared to 13.4%.

The number of subprime loans that were behind in payments soared to 29.08%, compared to 18.32% in the year-ago period.

In the subprime loan category, 12.63% of the loans were behind in payments by 90 days or more, more than twice the year-ago rate.

The company noted the market for new loans, particularly loans that lenders can’t sell to government-backed mortgage companies, declined substantially during the quarter as underwriting standards began to tighten industrywide following the subprime mortgage meltdown.

Earnings from the company’s loan production unit also suffered because gain-on-sale margins the company had expected to rake in did not materialize.