An improved computing architecture for managed-account transactions is presented. In accordance with embodiments, responsive to receiving a request to purchase one or more units of an asset for an account of a client, a computing system may identify a customized rule for the account, the client, and/or the asset. Responsive to determining that the request meets each of one or more criteria specified by the customized rule, the computing system may, for each of the unit(s), instantiate, in an account object associated with the account and stored within a client object associated with the client and stored in a memory of the computing system, an object representing the unit and may store, in the memory, an indication of a price and time at which the unit was purchased and data associating the indication with the object representing the unit.