Ideas for the Mambu Banking Engine

Locking amounts on deposit accounts


  1. Customers working with credit card transactions need a way to lock "authorized" amounts on savings accounts, without effecting accounting and (overdraft) interest calculations.
  2. Authorized amounts lead to two account balances: a) Actual Balance and b) Available Balance, where as the latter is the Actual Balance minus the sum of all authorized amounts.
  3. For (overdraft) interest calculations a) should be used, for sufficient fund checking on withdrawals b) should be used.

This is similar to guarantees and funding sources for loans, but for current accounts.


If an authorized / locked amount would be debited from a current account, this transaction would have accounting and (overdraft) interest calculation implications. This is not desired as the transactions are not yet effective.


a) New transaction state inside the transaction lifecycle:

The current transaction lifecycle of 1) "applied", 2) "reversed" and upcoming in APP-136 "Transaction States" 3) "pending approval" could be further extended by adding 4) "authorized" / (or "locked" or "frozen"). A valid transaction lifecycle would then go from: (optional) pending approval -> (optional) authorized -> applied -> (optional) reversed.


b) New transaction type:

A new transaction type "authorization"  (or "lock" or "freeze") could be introduced. If an authorization becomes effective, is cleared or expires, it would be reversed and in case of effectiveness a withdrawal transaction is posted.

  • Thomas Bachmann
  • Jan 27 2016
  • Will not implement
  • Attach files
  • Monica Branzan commented
    17 Oct, 2016 03:56pm

    Mambu will not implement an "Authorised State", this functionality will in fact be covered by Authorisation Holds implementation according to market standards, via which Available Balance functionality will be exposed and as such 'holding" amounts until they are settled, this will be delivered with DPS-5 feature