Keep calculation from last months in the next ones

[Anonymous]

Hello,

Every month I have 3 columns: Stock, Forecast and a calculation RiskBBD.

I need to calculate RiskBBD in such a way that it will keep the result from previous months in the next months.

RiskBBD = Stock-Forecast, but if last month RiskBBD was negative, it will be Stock-Forecast+LastMonth RiskBBD. If In one month I won't have stock and Forecast, it will show me the result (RiskBBD) from the last month.  

Basically, if last month BBDRisk <> 0  AND <0, THEN Stock-Forecast+RiskBBD Last month,

                   if last month BBDRisk <> AND >0, Then Stock-Forecast

                      if last month<>BBDRisk 0 AND this month =0, THEN Last month RiskBBD  (The same in the next months with the last RiskBBD)

                         if last month BBDRisk =0, THEN Stock-Forecast

Here is the Calculation in Excel:

[lbendlin]

Please provide sample data that covers your issue or question completely.
https://community.powerbi.com/t5/Community-Blog/How-to-provide-sample-data-in-the-Power-BI-Forum/ba-...
Please show the expected outcome based on the sample data you provided.

https://community.powerbi.com/t5/Desktop/How-to-Get-Your-Question-Answered-Quickly/m-p/1447523