Mortgages are like call options on stocks
An option contract provides the contract holder the option to force the contract writer to either buy or sell a particular asset at a given price. A typical option contract has an expiration date, and if the contract holder does not exercise their contract rights by a given date, they lose their contractual right to do so. An option giving the holder the right to buy is a “call” option, and the option giving the holder the right to sell is a “put” option. The writer of an options contract is typically paid a fee or a premium for taking on the risk that prices may move against their position and the contract holder may exercise their right. The holder of an options contract willingly pays this premium to limit their losses to the premium paid if the investment does not go as planned. Most options expire worthless.
Mortgages took on the characteristics of options contracts in the Great Housing Bubble. Speculators utilized 100% financing and Option ARMs with low teaser rates to minimize the acquisition and holding costs of a particular property. The small amount they were paying was the “call premium” they were providing the lender. If prices went up, the speculator got to keep all the gains from appreciation, and if prices went down, the speculator could simply walk away from the mortgage and only lose the cost of the payments made, particularly when this debt was a non-recourse, purchase-money mortgage. Another method speculators and homeowners alike used was the “put” option refinance. Late in the bubble when prices were near their peak, many homeowners refinanced their properties and took out 100% of the equity in their homes. In the process, they were buying a “put” from the lender: if prices went down (which they did,) they already had the sales proceeds as if they had actually sold the property at the peak; if prices went up, they got to keep those profits as well. The only price for this “put” option was the small increase in monthly payments they had to make on the large sum they refinanced. If fact, on a relative cost basis, the premium charged to these speculators and homeowners was a small fraction of the premiums similar options cost on stocks. Of course, mortgages are not option contracts, and lenders did not view themselves as selling option premiums to profit from the premium payments; however, speculators certainly did view mortgages in this manner and treated them accordingly.