BlackRock, the world's largest fund group, is a leader in exchange-traded instruments.
Credit Suisse said that at the end of November its so-called ETF business was managing assets worth 16 billion Swiss francs ($17.3 billion), and that the sale was expected to be completed by mid-2013.
The bank did not disclose the terms of the deal which, it said, still needed approval from regulatory authorities.
Swiss media were quick to note that former Swiss National Bank chairman Philipp Hildebrand joined BlackRock last year after stepping down as head of the central bank.
Hildebrand resigned following a controversy over a currency transaction made by his wife through a joint account held with him.
He was named as vice-president of BlackRock in June 2012 following his SNB resignation five months earlier.
"This is an important strategic step in an industry that requires significant scale," Credit Suisse said of its planned acquisition.
Thursday's announcement was not unexpected, yet Credit Suisse saw its share price rise 0.84 percent to 25.17 Swiss francs in midday trading on a Swiss
stock market marginally down.
"The ETF business is generally a low margin business which needs scale to make it attractive," Vontobel analyst Terese Nielsen said in a note, pointing
out that BlackRock is one of the world's largest ETF providers.
The sector meanwhile currently represents only about four percent of Credit Suisse's managed funds, she said.
ETFs, which enable investors to invest in a bundle of assets in the same category, are traded on the stock exchange in the same way as individual stocks.
They represent assets such as stocks, commodities and bonds.