There are many amounts that are received, sent, stored, and maintained by Portico. The purpose of this section is to define some of the key amounts that appear in the messages, reports, and settlement:

Key Amount	Description
Amt	This may also be referred to as original amount or request amount. This is the amount that the POS originally sent to Portico for a particular transaction. This amount is kept by Portico for the life of the transaction and is not altered.
AuthAmt	This may also be referred to as an authorized amount. This is the amount that was originally authorized/approved by the issuer. In the case of a full approval, this matches the Amt. In the case of a partial approval, this is equal to or less than Amt. This amount is kept by Portico for the life of the transaction and is not altered.
SettlementAmt	This is the amount that is used if the transaction is settled. When a transaction is first approved, this matches the AuthAmt. This amount is maintained by Portico over the life of the transaction. This is altered by reversals, transaction edits, incremental transactions, etc.

Maximum Size of Amount Fields

Portico supports a maximum of 12 digits in amount fields, inclusive of decimal places. Please note that the GNAP-UK Authorization Platform supports a maximum of 11 digits for amount values, inclusive of decimal places.

Currency and Amounts

Portico supports many different currency codes. The currency codes for a TID must be one that is supported by the settlement systems of the Authorization Platform. The format of any amount fields in a transaction request must be consistent with the currency code of the TID.

Currency Minor Units	Amount in Transaction Request	Format to Issuer
0	1 1.0 1.1	1 1 Returns Error
2	1 1.1 1.11 1.111	1.00 1.10 1.11 Returns Error
3	1 1.1 1.11 1.111 1.1111	1.000 1.100 1.110 1.111 Returns Error

Estimated and Final Amounts

Portico supports the option to indicate whether the amount requested in a credit transaction is Estimated or Final. This indicator is passed through to the host and the appropriate card brands for merchants processing on all authorization platforms. It is expected that CreditAuth or RecurringBillingAuth is used when the amount is estimated (for example, where a tip may be added afterwards or an hourly rental is not returned on time), and that CreditSale or RecurringBilling is used when the final amount is known at the time of the request.

To indicate whether the transaction amount is estimated or final, send the AmountIndicator field.