Opening balance as comparative issue

Hi all,

Long time lurker, first time poster (mainly as I've always managed to find my answers in other posts). I'm having an issue with a matrix table comparing period ending balances from one month/quarter-end to another. I have security level information grouped by asset class.

One column for my current period balance (as selected by a Year - Quarter - Month slicer) and then another column for my comparative (I'm using a selection slicer and switch formula to change this comparative between the prior month-end, quarter-end or year-end).

The issue I'm having is that my sub-totals by asset class are correct, but when I drill down to the security level detail my prior period comparative does not contain all securities held at that prior period date. It is only showing rows for securities held at the current period date (i.e. where a security has been sold it does not show me a $0 current balance next to a >$0 balance for the prior period). Example below (I've blanked out names for confidentiality reasons).

Measures for my current and prior period market values are:

MV_Current Period End = CALCULATE(sum(FACT_FinancialData[BS.Base Market Value Clean]),LASTNONBLANK('Date Table'[Date],CALCULATE(SUM(FACT_FinancialData[BS.Base Market Value Clean]))))


UGL_Prior Quarter-End = OPENINGBALANCEQUARTER(sum(FACT_FinancialData[BS.Base Market UGL]),'Date Table'[Date])

My asset type is contained in a mapping table with the security name/description in a dimension table as follows:

Any help would be greatly appreciated!