I work in that industry, and that's not quite the case any more. Bonuses for junior analysts can reach up to around 50% (which nearly every other profession could never expect), but they would never exceed base salary.

Anybody saying otherwise has been reading too many tabloids.

You can find out more details about salaries in this area by using a site like glassdoor.com. This 100%+ bonus culture is simply not true (now).