When MED applies
A Pix transaction enters the MED process when a financial institution identifies the need for formal, regulated investigation, typically in cases such as:
- Fraud (phishing, account takeover, social engineering)
- Unauthorized transactions (user did not approve the payment)
- Operational errors (duplicate sends, incorrect recipient, wrong value)
- System or processing failures causing financial impact
Regulatory MED lifecycle
Every MED case follows a strict set of states defined by BACEN. Institutions must comply with the deadlines and response requirements at each stage.
Lifecycle overview
Figure 1. MED lifecycle stages and transitions
Valid reasons for MED disputes
A MED case must be opened under one of the regulated dispute categories:
| Code | Category | Examples |
|---|---|---|
| FRAUD | Fraudulent activity | Account takeover, scams, phishing |
| UNAUTHORIZED | Transaction executed without user consent | Stolen device, hijacked credentials |
| OPERATIONAL_ERROR | Execution mistake | Duplicate send, wrong recipient, incorrect amount |
| SYSTEM_ERROR | Technical fault | System malfunction, processing failure |
Possible outcomes
| Outcome | Result |
|---|---|
| APPROVE | Full refund must be processed |
| PARTIAL | Partial refund allowed (case-specific) |
| REJECT | No refund; case is closed |
| COMPLETE | Administrative closure after execution |
MED process — step-by-step flow
Below is the regulated MED process followed by all Pix institutions:
1. Validation
- Transaction exists and is in COMPLETED state
- Transaction age ≤ 30 days
- Minimum value R$ 1,00
- No existing open MED case for the same transaction
2. Evidence collection
- Fraud markers from DICT
- Internal risk analysis
- Upload of evidence (documents, screenshots, logs)
- Compliance verification
3. Case creation
- MED ID assigned
- Regulatory deadlines computed (7 / 10 days)
- Notifications sent to involved institutions
- Timeline and audit trail started
4. Analysis phase
- Examination of submitted evidence
- Evaluation of counterpart’s response
- Application of internal and regulatory rules
5. Decision
- Refund executed via pacs.004 (if approved)
- Ledger postings applied (debit/credit)
- Institutions notified
- All events logged for audit
6. Completion
- Case moves to COMPLETED, REJECTED, or EXPIRED
- 90-day retention period begins
- Evidence archived and audit trail locked
Integration points
Although MED is a regulatory process, it interacts with core Pix components:
| Component | Role |
|---|---|
| DICT | Provides fraud markers, key metadata, and ownership information |
| SPI (pacs.004) | Executes refund movements between institutions |
| Midaz Ledger | Applies debit/credit movements for approved cases |
| Pix Core Services | Coordinates lifecycle, deadlines, notifications, and SLA controls |
Compliance expectations
Institutions must ensure:
- Enforcement of all regulatory deadlines
- Cryptographic protection of evidence files
- Full audit trail including timestamps and event logs
- Standardized MED communication with counterpart institutions
- SLA monitoring and status tracking
- Consistent customer notification logic
- Proper use of dispute categories and reason codes
Relationship with refunds and reversals
While refunds and reversals are standard Pix operations, MED is the regulated mechanism used when:
- The refund is tied to fraud or unauthorized activity
- The originating institution disputes the transaction
- Additional evidence and regulated communication is required