The co-founder, chief executive officer and chairman of women's apparel firm St John Knits International Inc, Bob Gray, on Monday announced he will retire from the firm next month.

The California-based company, whose brands include St John and St John Sport by Marie Gray, said in a statement Mr Gray's CEO duties will be shared by Kelly Gray, co-president and creative director, and Bruce Fetter, co-president and chief operating officer.

Marie Gray, who co-founded the company with her husband, will remain head designer, while Roger Ruppert, senior vice president and chief financial officer, will be promoted to executive vice president and chief financial officer.

"I am extremely pleased with the partnership that has developed between Kelly and Bruce, with each complementing the other", said Mr Gray, who has agreed to remain as honorary chairman and board member.