9F59

Offline Counter Balance is the transaction-count equivalent of 9F58's spending-amount tracking: a second, parallel offline transaction counter M/Chip Advance maintains on the card, related to both 9F58 and the further M/Chip-proprietary counter C6. Where 9F58 tracks how much money has accumulated offline against a second ceiling, 9F59 tracks how many transactions have accumulated against a second, independent count limit - the same design principle of maintaining more than one parallel risk counter, applied to transaction count rather than amount. It's a single byte, but a card's own risk-management logic can decline offline specifically because this second counter, not the primary one, has been exhausted, which is exactly the kind of decline reason that looks unexplained from outside M/Chip's own proprietary counter model unless the analysis tooling actually understands 9F58 and 9F59 as a distinct pair from whatever primary counters the core specification already defines. See Mastercard M/Chip Advance Issuer Guide.