BlackRock has previously said it targets 5 percent "organic" growth from new business overall, with low-single digit growth rates in its institutional business, high single-digit growth in retail and low double-digit growth in iShares, its booming ETF business.

But BlackRock CFO Gary Shedlin, speaking on Wednesday at a Goldman Sachs event, said the company is "less committed to exactly where that growth is going to come from."

In the most recent quarter, reported in October, BlackRock's retail and institutional organic asset growth was zero percent, while iShares was 15 percent.

"While we still reaffirm that as an aspirational goal, I think we probably feel a little less committed to exactly where that growth is going to come from, primarily because we're seeing massive adoption by both retail and institutional investors into ETFs."

BlackRock cut fees on a set of its ETFs in October, including lowering the annual fee on its stock-tracking iShares Core S&P 500 ETF to 0.04 percent from 0.07 percent.

Shedlin said the company had studied its peers and saw an opportunity "to get a 12- to 18-month head start" to win over new clients and cash by cutting fees.

He said while slicing investor's expenses cost money up front, the asset manager is well on its way to earning that revenue back due to the company gaining market share.

The relatively low-cost iShares Core series that saw those price cuts has taken in about $15 billion since the announcement, Shedlin said, reflecting about 40 percent organic growth in two months.

As rates rise, bond investors could face losses. But Shedlin said nearly two thirds of the company's $1.6 trillion in fixed income assets are institutional, and those clients tend to stick around.

He said the company's money-market funds business also could earn more as the company drops fee waivers that it initiated as clients struggled with a low rates.

BlackRock's lucrative business of lending out the stocks and other securities it holds in its funds, often to speculating investors, also could throw off more revenue as the collateral it collects gets placed in higher-yielding investments.

Shedlin said the company is also "under-penetrated" in relatively high-fee hedge funds, private equity and infrastructure businesses that can also expand.

(Reporting by Trevor Hunnicutt; Editing by W Simon and Bill Trott)

By Trevor Hunnicutt