* Sales rise 27%, up 8% excluding online distributors

* Net profit more than doubled thanks to one-off gain

* Double-digit growth in mainland China, U.S.

* Online distributors have operating loss

* Shares down 1.2%, lag sector index (Adds management, analyst comment, background, shares.)

By Silke Koltrowitz

ZURICH, May 17 (Reuters) – Luxury goods group Richemont reported weak profitability in its watch business and online distributors in its past financial year, taking the shine off a solid sales performance in China and the United States.

Investors had been worrying about demand for luxury goods in Richemont’s two biggest markets after Swiss watch export figures showed sluggish shipments this year and luxury rival Kering recorded slowing U.S. growth for its Gucci brand.

Richemont, known for