Igor Toronyi-Lalic points out that the proportion of workers in the City who are from ethnic minorities is five times that in the arts, and says:
The evil scumbags who work in the City appear to be doing a better job at being modern and liberal than the state-subsidised art world.
Why? One reason, as Simon says, is a selection effect; Indians tend to study numerate subjects, which disposes them to enter finance rather than the arts.
But there's another reason - the Ron Atkinson effect. In the 70s, pro football was overwhelmingly white. Then BFR selected the "three degrees" - Batson, Regis and Cunningham - which paved the way for an influx of black players into top sides.
BFR did not do this because he had advanced, liberal opinions; we later learned that he didn't. He did it because players of the calibre of Regis and Cunningham were so good they improved his team greatly.W hen racism met the desire to win games, racism lost.
This illustrates a point made by Gary Becker back in 1957. He pointed out that competition was the enemy of discrimination and monopoly its friend. A company that refused to hire blacks or women even if they were good workers would lose out to firms that did hire them. And subsequent research has proved him right. For example, studies have found that when US banks became exposed to more competition in the 80s and 90s, gender (pdf) and racial (pdf) pay gaps narrowed.
This helps explain the difference between the arts and banking. Granted, banks as an industry are massively (pdf) subsidized. But within the bubble there's competition between banks. And in many banking jobs, there's a clear measure of performance; does the guy make money or not? Competition and the ease of measuring performance combine to make banks want to hire the best person they can, regardless of colour.
By contrast, there's less competition between arts groups and less clarity of measuring performance*. This gives arts companies more room to prefer the second-rate white guy - a breed of whom the world has never had a shortage - over the better black.
Now, you might think all I've said here is standard pro-market stuff. But there's an implication for the left. We don't achieve equality merely by having politically correct liberals in positions of power (especially if such"liberals" are merely self-righteous hypocritical little pricks). We achieve it by having the right institutions and mechanisms. Structure matters more than agency.
* I'm talking matters of degree here; it is possible for duffers with political skills to do OK in banking, but it's probably tougher.