Hong Kong's Chow Tai Fook Jewellery Group Ltd said on Wednesday it has agreed to buy U.S.-based diamond jeweller Hearts on Fire Co for $150 million in a move to extend its high-end product range.

Chow Tai Fook, the world's largest jewellery retailer by market value, said in a statement it will buy 100 percent of the supplier of bridal and fashion jewellery from co-founder Glenn Rothman and other investors. Established in Boston in 1996, Hearts On Fire products are sold in 31 countries.

Hearts on Fire reported audited net sales of $104.8 million for 2013, up from $99.3 million a year earlier, Chow Tai Fook said. About 75 percent of its jewellery sales in 2013 were priced between $1,000 and $10,000, with the most of the remainder carrying price tags above $10,000.

Chow Tai Fook on Tuesday reported a 32 percent jump in its profit for the year ended March, helped by strong demand for gold products early last year.