Circle is exploring potential acquisitions, primarily by Coinbase, according to Fortune.

Circle Internet Financial, the issuer of USDC (USDC), is moving forward with its planned initial public offering. But behind the scenes, the stablecoin

Circle Internet Financial, the issuer of USD coin (USDC), is pressing ahead with its planned initial public offering. But the firm has also been engaged in informal sale talks with Coinbase (COIN) and Ripple (XRP), two major cryptocurrency firms, in recent months, according to four people familiar with the matter.

Circle is valued at about $4 billion to $5 billion. It is unclear what terms, if any, have been discussed between the parties.

“If Coinbase wanted to buy them, Circle would sell in a heartbeat,” one banker familiar with the matter told Blockworks.

While plans for an IPO are still in place, no IPO terms or roadshow have yet been announced, and it is unclear whether the company will pursue a direct listing.

Coinbase is likely the best-suited buyer for Circle. The two firms co-founded Centre Consortium in 2018 to issue USDC and still share revenue from reserve interest.

Coinbase has favorable terms, including a 100% share of revenue from USDC held on its platform. It also holds influence over Circle’s partnership decisions and intellectual property rights.

Coinbase CEO Brian Armstrong also said on May 14 that Circle’s IPO plans don’t affect their commercial ties and hinted at being open to future deals, despite already disclosing an interest in expanding through acquisitions.

Coinbase has already ramped up its M&A activity this year with the acquisitions of Deribit and Spindle.

Circle’s IPO hopes may also be buoyed by eToro’s recent strong market debut. However, the possibility of a strategic sale remains on the table.

Meanwhile, Ripple is also said to have made an offer of around $4 billion to $5 billion for Circle, which was reportedly rejected.

However, Blockworks reported in March that executives at the two firms had discussed the potential of a merger.

Ripple could reportedly leverage its large XRP reserves—which are valued at over $100 billion when including tokens in escrow—to fund a deal. But Coinbase, with $8 billion in cash and the ability to raise capital quickly through the public markets, is the stronger financial contender.

A spokesperson for Circle declined to comment.