Brown Brothers Harriman ended 2012 with $7.5 billion in assets, up from $3.8 billion in 2011. The company's flows totaled $3.2 billion.

In the third place in the Strategic Insight survey was Stone Harbor, which enjoyed a flows rate in 2012 of 53 percent. The company's assets in 2012 and 2011 stood at $5 billion and $3 billion respectively, while flows for 2012 totaled $1.6 billion.

Turning to passively managed stock and bond funds and ETFs, the report reveals that ALPS Advisors Inc. was the fastest growth manager of these funds, recording a flow rate in 2012 of 109 percent. Assets for the company hit $5.8 billion and $2.7 billion, respectively, for 2012 and 2011, while the firm's flows in 2012 reached $2.9 billion.

In second place among the passive fund managers is Wisdom Tree Asset, which enjoyed a flow rate of 46 percent. Assets in 2012 and 2011 came to $15.4 billion and $9.4 billion, respectively, while flows in 2012 hit $4.3 billion.

Guggenheim Fund Advisors nabbed third place in the survey with a 42 percent flow rate. Assets reached $4.6 billion and $3 billion for 2012 and 2011, respectively, and flows reached $1.3 billion.

The survey adds that assets managed by exchanged-traded funds eclipsed $2.5 trillion and net flows exceeded $250 billion in 2012. Fund manager Vanguard captured about half of these annual flows.