Circle-Tether dispute puts stablecoin controls in focus

Circle won a $49 million arbitration fight on Tuesday after blocking a Tether-backed fund from its platform over suspected manipulative trading in USDC, according to newly public court filings detailed by the Financial Times. The dispute puts a private record behind a question that usually sits in regulatory speeches: who is allowed to use the rails behind a major dollar token, and on what terms.

Circle’s case was that Heka Funds’ redemption patterns raised questions about whether USDC was being used to distort flows and move dollars from Circle’s system toward Tether. That pushed the fight beyond a normal counterparty dispute. The filings describe an issuer trying to police conduct around its token before a regulator brought a case.

By the time Heka Funds sued, the money behind the relationship had made the stakes clear. The Malta-based investment vehicle, backed by Tether, sought $49 million in lost profits after Circle cut it off. The filings say Tether had invested about $800 million in Heka through a linked fund, equal to roughly 75 per cent of Heka’s assets. Circle defeated the broader claim and received about $166,000 in attorneys’ fees and expert costs.

Robert Dondero, the arbitrator, said in the arbitration record that Circle’s concerns were grounded in how the trading was allegedly structured, not in general reputational anxiety.

“Circle became appropriately concerned that Heka arbitrage was structured and possibly encouraged by Tether so that US dollars could be moved to Tether from Circle in exchange for USDC”

Robert Dondero, arbitrator

Governance contrast

For Circle, the language matters beyond the arbitration win. The company has pitched USDC as a more controlled and institution-facing stablecoin product, and the Heka dispute gives it a contested case to cite when it argues that market surveillance and access controls are part of the product. Circle saw a pattern it disliked, blocked the counterparty, defended the decision and prevailed after the fight became public.

That paper trail is useful because stablecoin oversight often becomes visible only after regulators intervene or a token breaks its peg. Here, private arbitration exposed the controls an issuer says it used before either happened. Circle can now point counterparties to a case in which an outside arbitrator accepted that its concerns were legitimate.

Heka’s Tether backing also hardens the competitive backdrop between the two issuers. Stablecoins are now a market worth about $307 billion, and the contest increasingly turns on trust, redemption rules and the credibility of the systems behind the tokens. Circle’s objection, as described in the filings, was that the pattern could use USDC as a bridge while redirecting dollars toward a Tether-linked strategy that Circle viewed as abusive.

The filings still stop well short of a regulatory finding against Heka or Tether. An arbitration ruling is not a government enforcement case, and the record does not show a formal market-manipulation charge from a public authority. The case sharpens the governance contrast between stablecoin brands without settling where commercial platform rules end and regulatory standards begin.

Heka rejected the allegation. A spokesperson said the fund had “never engaged in market manipulation” and had never been the subject of a regulatory investigation or proceeding involving similar misconduct. That denial preserves the legal line Heka has taken throughout the dispute. It also keeps the public value of the filings focused on how one issuer responded when it believed its own market safeguards were being tested.

The filings move the Circle-Tether rivalry into a more concrete register. Scale, distribution and brand preference still matter in crypto payments. But Circle emerged with an arbitration win and a documented record of how it says it used platform controls to protect USDC. For institutions, counterparties and policymakers watching stablecoin plumbing, that is the piece likely to travel furthest.