Terminal Verification Results (TVR)
A five-byte bit field in which a payment terminal records everything that went wrong or looked suspicious during an EMV transaction.
While talking to the chip, the terminal runs a series of checks and sets a bit for each failure. Offline data authentication failed, the card has expired, the PIN try limit is exhausted, the amount exceeds the floor limit, cardholder verification did not succeed. The TVR lives in EMV tag 95 and travels to the issuer inside the authorisation request.
The decision comes from comparing the field against two sets of masks: the terminal's action codes (TAC) and the issuer's action codes (IAC) read from the chip. A set bit that matches a Denial mask declines the transaction on the spot; one that matches Online sends it to the bank. Anyone debugging a declined card payment will usually find the TVR to be the most informative field in the whole log.