Mastercard is offering Brazilian acquirers half of what they are claiming over the collapse of Will Financeira, known as Will Bank, along with several years of services such as fraud protection, Bloomberg reported on August 14, 2026. The card network’s total exposure to the failure is about R$5 billion, or close to US$950 million. Mastercard has already paid roughly half. The dispute is over the remaining R$2.5 billion or so.
Beyond the money, the case tests a basic question for card payments: who is the last line of defense for settlement when an issuer disappears?
A failed issuer left a hole in settlement
Will Bank was a fintech controlled by Banco Master. Brazil’s central bank halted Banco Master’s operations in November 2025, then appointed a liquidator, and police arrested its controlling shareholder. The central bank put Will Financeira into liquidation in January 2026. As a card issuer, Will was responsible for paying the network for purchases made by its cardholders. When it failed, those payments stopped, leaving a hole in the settlement chain after merchants had already been paid.
Acquirers pay merchants before issuers pay up
In the four-party model, a card transaction involves the cardholder, the issuing bank, the merchant, and the acquirer. The network does not lend money. It clears transactions, netting each participant’s positions, and then arranges net settlement. By that point, the acquirer has already paid the merchant. If the issuer defaults before settling its position, the loss has to land somewhere in the chain, and the question becomes who ultimately guarantees it.
- The cardholder pays the merchant by card.
- The acquirer pays the merchant, usually within one to two business days.
- The network clears the positions and calls funds from the issuer.
- The issuer settles its position. If it fails first, the money is missing, and the network must decide whether to advance it.
Mastercard says a new central bank rule doesn’t apply
Brazil’s central bank tightened its rules in 2026. Payment scheme operators, known in Brazil as payment arrangement institutors, must now ensure that funds reach the receiving party, using their own resources if necessary. The acquirers involved, including Redecard, Cielo, StoneCo, and PagSeguro, argue that this makes the network liable for every unsettled transaction. Mastercard counters that it owes only the amounts that came due in the month after the liquidation. It also argues that the rule, which card networks had until May 2026 to comply with, cannot apply retroactively to a failure that occurred in January.
| Issue | Mastercard’s position | Acquirers’ position |
|---|---|---|
| What the guarantee covers | Amounts due in the month after the liquidation | All unsettled transactions |
| Scope of the central bank rule | Not retroactive; compliance deadline was May 2026 | Applies; the network guarantees settlement |
| Proposed resolution | 50% of the claim, plus multiyear services | Full claim stands |
The outcome will set Brazil’s rule on settlement guarantees
The case matters beyond a commercial dispute. It tests a scenario that rarely plays out in practice: an issuer large enough to throw a network’s clearing out of balance across an entire market. Brazil also has many young fintech issuers whose risk profile differs from that of established banks and whose volumes have grown quickly. Whether the answer comes from a negotiated settlement or from a central bank position, it will set the local standard for how far the settlement guarantee extends.
For the acquirers, the problem is immediate: they have already paid merchants and now hold a claim against a network. For Mastercard, the issue is one of principle. Accepting the broadest reading of the guarantee would mean taking on the credit risk of every issuer in every market where it operates. The Brazilian negotiation will either shift or confirm that line, and that matters more than the R$2.5 billion at stake.