Blab Crypto
STJ Declares Crypto Payments Valid, Rejects Appeal Over I9 Coin in Property Sale
On 1 September 2026, Brazil’s Superior Tribunal de Justiça (STJ) delivered a decisive ruling in a case that has become a touchstone for crypto‑based contracts in the country. The court’s third panel rejected a special appeal filed by a seller who had agreed to receive part of the price for an apartment and a car in the cryptocurrency I9 coin, affirming that the asset’s volatility does not invalidate the contractual obligation to transfer it.
The dispute began when a saleswoman entered into contracts to sell an apartment worth R$850 000 and a vehicle worth R$180 000. In each case, the buyer was to pay a portion of the price in I9 coin: R$450 000 of the apartment and R$120 000 of the vehicle. The seller later sued, arguing that the payments made in cryptocurrency were null because the coin had been created to facilitate a pyramid scheme.
The Court of Justice of Santa Catarina (TJ‑SC) first ruled that the apartment sale was void. The buyers had paid only 53 % of the agreed price, prompting the court to terminate the contract. The vehicle sale, however, was upheld by the same court. The seller contended that the contractual provision for payment in I9 coin was illicit because it was allegedly used for fraud.
In its decision, the STJ dismissed the seller’s appeal. Minister Nancy Andrighi explained that transactions involving cryptocurrencies are valid under Brazilian law because there is no legal seal that would invalidate them. She noted that accepting crypto as payment is optional and that the business risk lies with the parties who agree to the arrangement. The court emphasized that the obligation to transfer cryptocurrency can only be converted into losses and damages with payment in Reals in exceptional situations, such as fraud or impossibility of compliance.
The court also highlighted the current state of the I9 coin. According to blockchain data, the coin is trading at close to zero due to a lack of liquidity, indicating that market interest has waned. Despite this, the court reaffirmed that the mere fluctuation of a cryptocurrency’s value does not invalidate a legal contract that specifies its transfer.
The decision clarifies that, under Brazilian law, parties who accept cryptocurrency as payment assume the inherent volatility risk. The court’s ruling does not create a new legal framework for digital assets but confirms that existing contract law applies to crypto transactions.
At present, the case remains unresolved only in the sense that the seller’s appeal has been denied and the lower court’s rulings on the apartment and vehicle sales stand. No further appeals have been filed, and the parties are expected to comply with the contractual terms as interpreted by the STJ.
The ruling is significant for the Brazilian market, where the use of digital assets as payment continues to grow. It signals that courts will uphold crypto‑based contracts unless there is clear evidence of fraud or other illegal activity. The decision may influence how future agreements involving cryptocurrencies are drafted and how parties manage volatility risk.
The case also underscores the importance of liquidity and market confidence in digital assets. With I9 coin’s value near zero, the risk of loss for parties who accept it as payment is high, a fact that the court acknowledged but did not alter the legal validity of the contract.
In summary, the STJ’s ruling affirms that cryptocurrency payments are legally enforceable in Brazil, that volatility risk is borne by the parties, and that conversion to fiat currency for damages is limited to exceptional circumstances. The decision provides a clear precedent for future disputes involving digital asset payments in the country.
The dispute began when a saleswoman entered into contracts to sell an apartment worth R$850 000 and a vehicle worth R$180 000. In each case, the buyer was to pay a portion of the price in I9 coin: R$450 000 of the apartment and R$120 000 of the vehicle. The seller later sued, arguing that the payments made in cryptocurrency were null because the coin had been created to facilitate a pyramid scheme.
The Court of Justice of Santa Catarina (TJ‑SC) first ruled that the apartment sale was void. The buyers had paid only 53 % of the agreed price, prompting the court to terminate the contract. The vehicle sale, however, was upheld by the same court. The seller contended that the contractual provision for payment in I9 coin was illicit because it was allegedly used for fraud.
In its decision, the STJ dismissed the seller’s appeal. Minister Nancy Andrighi explained that transactions involving cryptocurrencies are valid under Brazilian law because there is no legal seal that would invalidate them. She noted that accepting crypto as payment is optional and that the business risk lies with the parties who agree to the arrangement. The court emphasized that the obligation to transfer cryptocurrency can only be converted into losses and damages with payment in Reals in exceptional situations, such as fraud or impossibility of compliance.
The court also highlighted the current state of the I9 coin. According to blockchain data, the coin is trading at close to zero due to a lack of liquidity, indicating that market interest has waned. Despite this, the court reaffirmed that the mere fluctuation of a cryptocurrency’s value does not invalidate a legal contract that specifies its transfer.
The decision clarifies that, under Brazilian law, parties who accept cryptocurrency as payment assume the inherent volatility risk. The court’s ruling does not create a new legal framework for digital assets but confirms that existing contract law applies to crypto transactions.
At present, the case remains unresolved only in the sense that the seller’s appeal has been denied and the lower court’s rulings on the apartment and vehicle sales stand. No further appeals have been filed, and the parties are expected to comply with the contractual terms as interpreted by the STJ.
The ruling is significant for the Brazilian market, where the use of digital assets as payment continues to grow. It signals that courts will uphold crypto‑based contracts unless there is clear evidence of fraud or other illegal activity. The decision may influence how future agreements involving cryptocurrencies are drafted and how parties manage volatility risk.
The case also underscores the importance of liquidity and market confidence in digital assets. With I9 coin’s value near zero, the risk of loss for parties who accept it as payment is high, a fact that the court acknowledged but did not alter the legal validity of the contract.
In summary, the STJ’s ruling affirms that cryptocurrency payments are legally enforceable in Brazil, that volatility risk is borne by the parties, and that conversion to fiat currency for damages is limited to exceptional circumstances. The decision provides a clear precedent for future disputes involving digital asset payments in the country.
