President Obama still has some friends in the investment banking world. Chad Leat, managing director and chairman of Alternative Asset Group — Investment Banking Department at Citigroup Inc., is hosting a $10,000-a-plate dinner for Vice President Joe Biden on Aug. 24 at his home, The Barnyard in Bridgehampton. Leat is described in Hamptons Cottages and Gardens as a “banker, dedicated equestrian and imaginative host,” with an “elegant, but hip” home. On the table for discussion will undoubtedly be the economy and jobs. Probably not up for discussion will be that in 2008 Citigroup got a $45 billion government bailout in two installments.