Mastercard's dispute regime maps roughly onto Visa's at the level of headline reason codes, and that resemblance is enough to make merchants treat them interchangeably. They are not. A merchant defending a Mastercard 4853 with the evidence and timing of a Visa 13.1 case loses cases that would have won on the actual Mastercard rules.
Mastercard gives the merchant 45 calendar days from the chargeback message date to respond, longer than Visa's 30, and a merchant who treats the Visa deadline as universal misses Mastercard cases that could have been argued more carefully. The reason-code structure differs in a more consequential way. Mastercard 4853 is not a single reason code in the way Visa 13.1 is; it is an umbrella covering multiple consumer-dispute sub-conditions (4853-NA "Goods Not Received," 4853-NF "Not as Described," 4853-NK "Cancelled Recurring," among others), each with its own evidence requirement. A merchant who reads 4853 as one thing addresses the wrong question; a merchant who reads the sub-condition the issuer actually filed under wins disproportionately.
Workflow differs too: Mastercard's second-presentment stage runs separately from Visa Claims Resolution, with specific Defense Document tagging and a sequenced pre-arbitration process that determines whether and how a case can escalate. The differences compound across a portfolio. A merchant doing meaningful Mastercard volume should either learn the Mastercard rules separately or accept that their Mastercard win rate will sit consistently below their Visa one, for reasons that have nothing to do with the underlying transactions.