The spreadsheet says 16 percent on a tax lien book and the realistic number is closer to 6, so which one is lying?
Start with a simple model, knowing it is too simple. Two hundred certificates, average face $2,200, statutory 16 percent, everything redeems inside 18 months. The spreadsheet returns a hair under 16 percent because all it does is compound the statutory rate. The realistic number lands far closer to 6 percent, and the interesting part is that most first-time buyers cannot defend that with a figure. They know costs are missing but not their names, and they cannot tell which one is the big one and which is the rounding error. So for people who have run more than a handful of these: what actually comes out of the 16 percent between the auction and the redemption check?