Create a Line Graph showing changes to a portfolio over time using the most recent values by month

Hi,

You may download my PBi file from here.

Hope this helps.

Thanks, this is it. So folks are aware or the OneDrive link inevitably dies, here's the logic. 

You need to create a calendar table (date dim) 

Calendar = CALENDAR(MIN(Data[Created_Date]),EOMONTH(MAX(Data[Created_Date]),0))

Sum your cost from the Data Table

TC = SUM(Data[Total Cost])

Use the following measure:

Measure = CALCULATE([TC],LASTNONBLANK(CALCULATETABLE('Calendar',DATESBETWEEN('Calendar'[Date],minx(ALL('Calendar'),'Calendar'[Date]),max('Calendar'[Date]))),CALCULATE([tc])))

Lastly, do the following:

Measure 3 = SUMX(CALCULATETABLE(VALUES(Data[Portfolio]),all('Calendar')),[Measure])

I had to replace the VALUES(Data[Portfolio]) with SUMMARIZE(Data, Data[Column 1], Data[Column 2], etc) to get what I wanted.