Your expectation of XIRR is correct. It returns an annualized rate for the
period specified.

Also -400% is impossible. The most you can lose is 100%.

My best guess is that it's a data error, but without seeing the data, it's
impossible to tell.

Regards,
Fred.

"Don Kline" wrote in message
...
I have a series of monthly transactions over several years. I have used the
XIRR function to find the ROR for each month, each quarter, and each
calendar
year. The client now wants a rate from inception. My expectation was I
would
get an annual rate for the entire period. However I feel that a -400% ROR
is
not accurate.

Is there anything different I need to do when the period is greater than
one
year?