VLOOKUP issue

Dear Forum,

I've encountered an issue with the vlookup function today.

I am working on a spreadsheet which keeps track of an Investment Portfolio:

Columns A, B, C contain Dates, Equity and Performance (in%) respectively.

What I want to do: In order to keep track of max drawdown values, I keep the minimum value in column B displayed at the top of my sheet.

Using vlookup, I tried to obtain the date on which this minimum value occured ( in column A).

so something like this :

=vlookup([cell containing max drawdown];[columns A,B,C];[A:A];False), but all I get as return is #NV.

In order to make sure this isn't down to me typing it wrong, I tried the following:

=vlookup([C50];[A50:C50];[A50];False) and also got #NV. Now I can get it to return the same number as my search criteria by changing it to

=vlookup([C50];[A50:C50];[C50];False) but that's all I managed.

Sorry I can't be more specific. I've tried making mock datasets and my approach seems to be working fine elsewhere.

Could it maybe be due to the fact that there are alot of similar values in the Performance column (C)?

Could somebody point me to where I might have gone wrong?

Thanks very much,

mathebauer