Circle Internet Corp.'s stock plummeted 5.63% during intraday trading on Thursday, following a significant analyst downgrade and growing concerns about competitive pressures in the stablecoin market.

Mizuho Securities recently downgraded Circle from neutral to underperform and slashed its target price from $85 to $50. The downgrade cites the Open USD (OUSD) alliance — comprising over 140 companies including BlackRock, Coinbase, Mastercard, Stripe, and Visa — as a structural threat to Circle's business model. Under the OUSD framework, reserve yields are distributed among participating partners rather than a single issuer, potentially driving industry-wide pricing compression and eroding Circle's medium-term profitability.

Mizuho further warned that upcoming revenue-sharing negotiations between Circle and Coinbase — USDC's largest distribution partner — represent an additional headwind, as Coinbase's involvement in OUSD could strengthen its bargaining leverage and further squeeze Circle's margins. The downgrade compounds pressure from USDC's declining circulation, which has fallen approximately $70 billion from its March high.