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July 23 (Reuters) - Omniture Inc OMTR.O, which provides online business optimization software, reported wider second-quarter loss on higher expenses, and forecast third-quarter earnings below market estimates, sending its shares down 14 percent.

The company posted second-quarter net loss of $6.5 million, or 9 cents a share, compared with a loss of $4.1 million, or 8 cents a share, a year ago. Sales more than doubled to $71.6 million.

Excluding items, it earned 10 cents a share. On a non-GAAP basis, the company's revenue stood at $74.9 million.

Total operating expenses more than doubled to $52.8 million.

Analysts on average had expected the company to earn 11 cents a share, excluding exceptional items, on revenue of $74.4 million, according to Reuters Estimates.

Excluding items, the company expects earnings of 10 cents to 11 cents a share for the third quarter, and 41 cents to 46 cents a share for the full year.

For the third quarter, the company sees GAAP revenue of $76 million to $78 million and non-GAAP revenue of $78.5 million to $80.5 million.

Analysts were expecting a profit of 12 cents a share for the third quarter and 45 cents a share for the full year, both excluding items.

Shares of the company fell to $18 in trading after the bell. They closed at $20.97 Wednesday on Nasdaq. (Reporting by Eric Yep in Bangalore; Editing by Deepak Kannan)