You will have this problem whenever the number of days is even... the even
root of a negative number is imaginary. I'm not sure what your calculation
is supposed to be doing, but you can force an answer by making the negative
number positive by using the absolute value function...

Abs((Beg. Value / End. Value)-1)^(1/number of days)

but, in my opinion, that **does** change the meaning of the equation's
answer.

Rick


"escapeman" wrote in message
...
Hi,
I'm struggling with an error on exponential computation and need an
expert's
help.
One of my investment's holdings is minus. ^^;;

When I tried to annualized the holding period yield, a minus number, it
gives me an error sign #NUM!.

Here is my formula I use. For
((Beg. Value / End. Value)-1)^(1/number of days)
something like
-7.59 % ^ (1/# of days)

How do I get a right number in this case??