Two U.S. financial giants, Boston-based Fidelity Investments and New York-based BlackRock, Inc., Wednesday announced a strategic alliance that promises increased access to exchange-traded fund products from BlackRock’s iShares division for Fidelity’s customers in the United States.

As part of the partnership, Fidelity will more than double its current online commission-free ETF offerings, and will create new ETF portfolio strategies using iShares as components within its managed account offering. Additionally, BlackRock will help support Fidelity’s future passive sector investment management efforts.

“Through this groundbreaking alliance between two financial services leaders, we will leverage our complementary strengths to deliver leading ETF products and research that are unmatched to more than 10 million Fidelity customers,” said Kathleen Murphy, president of personal investing at Fidelity Investments.

“We are thrilled to be joining with Fidelity to create an ETF manufacturing and distribution powerhouse,” said Mark Wiedman, global head of iShares at BlackRock. “This long-term partnership will enable millions of investors to maximize the value of ETF investing.”

Both companies will support this strategic alliance with personnel focused on delivering iShares ETFs to Fidelity customers through their respective retail and advisor networks, they said.