UPDATE 1-Ken Griffin's Citadel to return about $7 bln in profit to investors -source

(Adds details on funds performance and background throughout)Dec 12 (Reuters) - Billionaire Ken Griffin's Citadel is planning to return about $7 billion in profit to investors, a source familiar with the matter said on Tuesday.The U.S. hedge fund's flagship portfolio posted a 7.15% return in the first half of 2023, Reuters reported in July, outperforming the broader industry.Hedge fund performance has been a mixed bag in 2023, with equity hedge funds enjoying positive returns amid a rally in the stock market.Meanwhile, macro hedge funds, which bet on global economic trends, have had a more challenging year due to market volatility and geopolitical turmoil.Citadel Securities did not immediately respond to a Reuters request for comment. (Reporting by Carolina Mandl in New York and Pritam Biswas in Bengaluru; Editing by Anil D'Silva)