I recently completed a full inventory of our DC gear, and have been asked to also provide a Fair Market Value (FMV) of ALL IT assets. Additionally, I'll need to update these values on a quarterly basis. In the past I have used a few different methods. Some people suggest finding completed auctions on eBay, some say to go to a website that will provide values, others take the purchase value and calculate depreciation. As new technology comes out, the value of IT equipment is constantly changing. I'll need to find an efficient and accurate way to place a value on our equipment, specifically servers (memory, procs, drives) storage and network gear.

What is the best method of determining the FMV for IT assets? What services or programs do you use? Thanks!