Is Hardi board siding the same thing as composite hardboard siding?

We live in a 5 year old house with Hardi board siding. Due to a possible company relocation we may have to move. The relocation company working with our company guarantees to buy the house if it doesn't sell in 90 days however they do not make this guarantee if your house has composite hardboard siding. So I am now trying to figure out if Hardi board is the same as composite hardboard siding. Thanks for any help you can give me.