Shares of Health Net Inc. fell after the Woodland Hills-based health insurer posted quarterly results that missed Wall Street expectations and said full-year earnings would be far lower than expected.

Net income for the second quarter dropped 17 percent to $76.7 million, or 71 cents a share, from $92 million, or 80 cents, a year ago. Excluding one-time items, profit was 74 cents a share, falling short by 2 cents the average estimate of 12 analysts surveyed by Bloomberg.

Chief Executive Jay Gellert said in a statement that Medicare health care costs were running higher than previous expectations. The company expects fewer new customers because of “further weakening in the economy,” Gellert said.

The company reduced its full-year 2008 forecast for adjusted earnings to a range of $1.97 to $2.03 a share, from its previous range of $3.45 to $3.55.

Health Net shares, which initially tumbled 15 percent on the report, recovered to close down 87 cents, or 3 percent, to $27.43 on the New York Stock Exchange.