Ben, your answer, as you indicated, is the short answer for the question. On a more complex level, we have to look at the opportunity cost of parting with 20% down payment versus, say, 5%. True, you save on PMI each month when you come up with a bigger down payment. But for the savvy and disciplined buyer, you can evaluate what you can get by investing the amount saved from the lower 5% down payment vs giving it up to save on monthly mortgage. Depending, on your tax bracket, the cost of your decision to pay a lower down payment is partially offset by the tax break you get for your mortgage interest. Thus, if you are a disciplined saver, you can come out well ahead in the end by paying a lower down payment and investing in the stock market both the saving on the down payment and the tax benefit of paying a higher mortgage interest expense on your bigger mortgage.