BlackRock ( BLK) shares rose 4% Wednesday morning as the asset manager posted better-than-expected quarterly results on record assets under management (AUM).

BlackRock posted a 21% fourth quarter jump in profit after buoyant equity markets increased income from fees and drove its assets to a record high of $11.6 trillion, the world's largest money manager said on Wednesday.

BlackRock said in its fourth-quarter earnings report Wednesday that assets under management jumped to a record $11.55 trillion, up from $10 trillion a year ago. Analysts surveyed by FactSet had expected BlackRock to report a record $11.