Several executives in Barclays' hedge fund financing unit are leaving to join other firms, the latest sign of churn in global prime brokerage ranks as banks realign their businesses under new regulatory constraints.

Mark Bailey, the global head of treasury for Barclays's equity-financing business, is joining trading firm giant Two Sigma Investments, according to people familiar with his plans. Bailey, a managing director based in New York, joined Barclays in 2011 from Bank of America's Merrill Lynch unit. He didn't respond to requests for comment.