The rising demand for medical and annuity insurance by the rapidly graying population boosted revenues at many of the nation's six largest life insurers in the first half of fiscal 2005, according to earnings reports released Monday.

Surging stock prices backed by a recovering economy also helped the industry's financial health, which had been hit hard the last few years.

Annualized new premium income -- a recently focused measure almost equivalent to revenue at other businesses -- jumped at three insurers, including Nippon Life Insurance Co. and Mitsui Mutual Life Insurance Co.

The third, and third-largest, Sumitomo Life Insurance Co., saw the largest gain at 26.2 percent from the same period last year, amounting to 99.3 billion yen.

Sumitomo's annualized premium income from policies in force rose for the first time in nine years by 0.3 percent.

"The medical and pension sectors for middle-aged people and seniors continued to grow in fiscal 2005, and cancellations also declined," said Koji Hanaoka, managing director at Sumitomo Life.

"That's why the year-on-year change on income returned to the plus side," he said.

But new premium income at Meiji Yasuda Life Insurance Co. tumbled 25.6 percent to 50.1 billion yen, and its new policies slid 29.4 percent.

Meiji Yasuda's slump came after the Financial Services Agency ordered the insurer in February and October to suspend some policy sales over its failure to pay legitimate claims.

Policies in force -- a measure of total business volume -- meanwhile continued to fall at six insurers due to intensifying competition with U.S. rivals.

Customers' shift to medical coverage from death coverage at each domestic insurance firm also reduced the value of outstanding policies because a medical plan is less expensive than death coverage.

The combined outstanding balance of contracts at all six firms stood down 5.1 percent from a year earlier to 872.5 trillion yen.

The six firms are Nippon Life, Dai-ichi Mutual Life Insurance Co., Sumitomo, Meiji Yasuda, Asahi Mutual Life Insurance Co. and Mitsui.

The six insurers' volumes decreased amid fierce competition with U.S. life insurers, including American Family Life Assurance Co., which has long been popular in Japan for its cancer plans.

Aflac announced Monday its annualized new premium income jumped 5.2 percent year-on-year to 53.1 billion yen. Its policies in force rose 11.1 percent to 8.1 trillion yen.

Japanese insurers have traditionally been strong in sales of death benefits. But with the rapidly aging population, demand for cancer and other disease plans has been outpacing that of death benefits in recent years.

The life insurers' solvency margin ratio improved amid recovering stock prices, with Nippon Life's reaching 1,107.9 percent.

Asahi Life's ratio, the lowest among the six, marked 645.6 percent. The solvency margin ratio is a key gauge of an insurer's ability to pay its policyholders. A ratio under 200 percent obliges the government to issue an order for prompt corrective action.