Is there a function within MS Excel which helps to match a particular variable with a subset of a dataset and performs calculations on it?

I am currently doing a project and have been searching online for a solution but have not found one yet.

I have tried to enter a VBA code within excel based on the principles of VLOOKUP but does not provide me with the end goal.

This project entails doing a valuation. The whole dataset contains columns relating to a client code and a description of the investments held, together with their corresponding values. However, the value of one particular investment is not a real-time value, but has a corresponding row with an unrealized Gain/Loss. See below for more:

A subset of the whole dataset:

I am trying to find a solution whereby I enter a client code, and the whole client portfolio comes up (done that with a VBA function similar to Vlookup, which returns an array). I am trying to find a solution where the sum for the corresponding rows ex. Fund X and the unrealized G/L is performed automatically (and the other assets which have unrealized G/L), thereby saving lots of time switching between the client codes and calculating the value singularly for each asset.

I have been racking开发者_JAVA百科 my brain trying to find something and trying to use a combination of tools but have not been successful as yet. Any help would be appreciated. Thanks in advance.

Tried to use pivot tables and VBA functions based on VLOOKUP but to no avail. I am not so fluent in excel but have been trying to find solutions to similar problems online. This is my last resort.