The acquisition, for an undisclosed price, will give BlackRock a business with Sfr16 billion ($17.5 billion) under management and expand the buyer's footprint in the Alpine nation.

"The transaction significantly extends BlackRock's footprint in Switzerland, which is home to one of the deepest investor bases in Europe," BlackRock executive Joe Linhares said in a statement.

BlackRock has been extending its reach in German-speaking Europe to maintain its title as the world's biggest asset manager. About the time the Credit Suisse auction was announced in July, BlackRock said it would would buy the private equity fund-of-funds business of reinsurer Swiss Re AG.

BlackRock was also part of a consortium led by Brussels-listed financial investor RHJ International SA that paid €384 million ($499.2 million) for Deutsche Bank AG's BHF-Bank private banking unit in September.

The Credit Suisse ETF unit has a total of 58 funds includes $8.7 billion in nine Swiss funds. The remainder are in Ireland and Luxembourg. The business will be merged with BlackRock's iShares ETF division.

The deal is expected to close in the second quarter.

Credit Suisse is busily restructuring to boost capital by Sfr15.3 billion to appease both Swiss and European banking regulators. It's also working to with regulatory agencies to prevent depositors from hiding money from tax authorities.

Late last year the lender said it would combine its private banking and asset management divisions into one division, which would also include its domestic investment banking activities. Its international investment bank is its second main division.

The Swiss bank's shares edged up Sfr0.16 to Sfr25.10 in afternoon trading in Zurich.