Circle Internet Financial said it raised $400 million in a funding round that included investments from BlackRock, Fidelity, Marshall Wace LLP and Fin Capital.

Notably, a press release said BlackRock, the world's largest asset manager, "has entered into a broader strategic partnership with Circle, which includes exploring capital market applications for USDC."

"This funding round will drive the next evolution of Circle's growth," CEO and co-founder Jeremy Allaire said in the statement. The round is expected to close in the second quarter.

The issuer of the USDC stablecoin, currently with $51 billion in circulation across multiple blockchains, is going public through a SPAC (special purpose acquisition company) merger.

A source with knowledge of the deal told CoinDesk the latest fundraising round doesn't change the terms of the SPAC merger, which values Circle at $9 billion.

Circle previously raised $440 million in a funding round last May.

The firm has partnered with big names from the world of traditional finance in recent weeks. Circle said late last month that BNY Mellon would serve as a primary custodian of the assets backing USDC stablecoins.

According to Tuesday's press release, BlackRock will function as "a primary asset manager of USDC cash reserves."

UPDATE (April 12, 13:14 UTC): Adds new headline, Allaire statement.

UPDATE (April 12, 13:46 UTC): Adds details on valuation and custodial arrangements.