Principal Financial Group Inc. said second-quarter profits nearly doubled as its home mortgage business benefited from fees that homeowners pay to refinance their home loans, though its chief executive said mortgage activity could slow by year’s end.

Net income rose to $202.2 million, or 62 cents per share, from $120.2 million, or 34 cents, a year ago. Excluding one-time charges and gains, profits would have been $217.9 million, or 67 cents, compared with $186.5 million, or 52 cents, during the year-ago period. Revenues rose 3.3 percent to $2.41 billion from $2.34 billion.

Principal Residential Mortgage Inc. accounted for roughly one-fourth, or $45.1 million, of the company’s operating earnings, compared with the $24.8 million the subsidiary earned during the same quarter last year.

Principal Chairman and Chief Executive J. Barry Griswell said there are signs that the home refinancing boom is slowing. Wall Street analysts, too, cast doubt on whether the company’s earnings from its mortgage banking business can continue their rise.

“In our view, the general trend for mortgage banking earnings will be downward as origination volumes subside,” wrote Merrill Lynch & Co. analyst Edward Spehar in a report to clients.

Shares of Principal have risen about 24 percent in the past year. Griswell raised his expectations for the company’s full-year per-share profits to $2.45 to $2.50 from $2.25 to $2.40. In a conference call with analysts and investors, he said those expectations were based on an assumption that U.S. stock markets would rise 2 percent per quarter.

UBS Warburg analyst Andrew Klingerman wrote in a note to clients that the higher guidance “appears somewhat conservative even with the slowdown in mortgage production.”

The company also expects full-year losses on investments of $130 million, lower than the $170 million it had previously expected and less than half the $300 million it lost in 2002.

During the second quarter, Principal repurchased 3.8 million shares of its stock at an average price of $30.83 per share, completing a stock repurchase program that the board of directors had previously approved. Griswell said the board had given approval to another $300 million stock buyback plan.

The company has $500 million in excess capital that Griswell said it would use for the stock repurchases, acqusitions or other investments.

“There has been a lot of chatter about consolidation,” Griswell said during a conference call. “I would just say we’re in a strong position from a capital perspective and I think our options are open. I am more comfortable with modest acquisitions that we can fit with our core business, and that’s what you’re most likely to see from us.”