After the financial crisis in 2008 a lot of top talent fled the big banks and head to Silicon Valley; recently some of those same people who fled are now coming back to work for the very same banks; the growth in tech enabled financial services and the opening culture have both help to attribute to this change; in recent years tech firms like Google and Facebook are now on the receiving end of criticism that is making positions at those firms less desirable; big tech still hold the edge in top places to work, but banks have made a lot of progress in recent years and are pushing to be considered tech firms themselves. Source.