My HP 10bII+ is much faster than HP 12c!

[Gene]

One other comment. This multiple root IRR problem happens ** whenever ** there is a series of cash flows with multiple sign changes.

+ - + as in this case.

- + - + - etc, etc.

That is the initial sign something will be wrong with an IRR approach. NPV does not suffer this problem. It ** always ** gives the best answer when your cost of funds is known.