Citing an unnamed study, he said that performance at companies actually worsen after the roles are separated. He added that the bank's presiding director ensures that all board members get an equal say. Moreover, the board has the power to fire him and determine his compensation. Indeed, JPMorgan's board slashed Dimon's compensation in half in 2012 after the $6 billion trading debacle revealed lapses in risk management and delivered a blow to the bank's reputation. Shares of JPMorgan ended Tuesday marginally lower. Historically, the bank's stock has outperformed in the month following the investor day, on the back of bullish commentary. --Written by Shanthi Bharatwaj in New York >To contact the writer of this article, click here: Shanthi Bharatwaj. >To follow the writer on Twitter, go to http://twitter.com/shavenk. >To submit a news tip, send an email to: firstname.lastname@example.org.