Hong Kong based investment firm Fung Brands has finalised an agreement to take an 80% stake in French luxury fashion brand Sonia Rykiel founded by the designer around 40 years ago.

It follows the announcement at the end of last month of exclusive talks between the two parties.

The aim of the agreement is to develop Sonia Rykiel as "a truly global international luxury brand," a joint statement reads.

The Rykiel family will retain 20% of the label and the founder's daughter, Nathalie Rykiel, will continue to hold the post of vice-president.

Set up around a year ago by the Fung family, which controls sourcing giant Li & Fung, Fung Brands' brief is to acquire luxury brands. It has already purchased France's Robert Clergerie (shoes) and Belgium's Delvaux (leather goods).

Sonia Rykiel has seen its turnover stagnate at EUR90m over the past two years. However, Fung Brands' chief, Jean-Marc Loubier, estimates the brand's turnover could be doubled over the next five or six years as a result of international expansion.

Export markets currently account for about 50% of Sonia Rykiel's sales, the principal outlet being Europe.