# additionalTransactionReason The reason that more than one transaction represents the subscription period. ``` let additionalTransactionReason: Transaction.AdditionalTransactionReason? ``` ## Discussion This value is `nil` if one transaction represents the whole period. When it isn’t `nil`, evaluate every transaction in the period together to get the number of seats in the period. For example, when the group purchaser adds seats partway through a period, the purchase creates a second transaction for the added seats, and both transactions have a reason of [`seatAddition`](/documentation/StoreKit/Transaction/AdditionalTransactionReason-swift.struct/seatAddition). The subscription’s seats for the period are the seats on the period’s transactions that aren’t revoked. Adding seats doesn’t set [`isUpgraded`](/documentation/StoreKit/Transaction/isUpgraded). At the next renewal, one transaction covers all the seats again. For more information, see [Managing the life cycle of multiseat subscriptions](/documentation/StoreKit/managing-the-life-cycle-of-multiseat-subscriptions). --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)