Calculate month to date returns, index and match

Hi

I would be grateful for someone's help

I have a spreadsheet with the daily value and percentage change of an index. Column A shows the dates, column B is the value of the index and column C shows the percentage change each day. Cell C2 is the end date (today) of the data range.

See attached spreadsheet.

I have a series of calculations on the same worksheet which shows the 1 month, 3 month, 6 month, year to date and returns since inception which work off the date in C2. Therefore as I change the date in C2, the output changes for the 1 month, 3 month etc.

The problem I have is with the month to date calculation. I have the year to date formulae working correctly, which was solved on here before, see below.

=SUM(INDEX($B:$B,MATCH($C$2,$A:$A))/(INDEX($B:$B,MATCH(DATE(YEAR($C$2)-1,12,31),$A:$A))))-1

Can someone help me change this formulae to work for month to date?

Thanks

Nick

A copy of the spreadsheet is attached.