Economic theory implies that the two should be tightly correlated, but history suggests otherwise
Mortgage interest rates will rise. We can't be sure exactly when rates will begin to climb or by how much, but we know what's coming. Since 2009, other than for a three-month period, average monthly 30-year fixed mortgage interest rates have been at or below 5%. Historically, that's completely unprecedented: average rates had never even hit 5% prior to 2009. Will home prices be affected when rates increase to more sustainable levels?
This is an important question in the context of whether or not to buy a home in the near-term. In a post last week, I explained that the current environment for home buying is relatively favorable. In particular, I said that as interest rates rise, homes will become less affordable, since mortgage payment size will increase at a given price point. Several readers objected to this line of reasoning, saying that home prices will decline farther as interest rates rise.
What Happens When Mortgage Interest Rates Rise?
Their logic is sensible enough. To understand it, let's imagine a hypothetical universe of perspective home buyers and homes. For simplicity, let's say there are three buyers and four homes for sale. Here's how the market looks (let's also assume no down payments to make things easier):
So at last week's average mortgage interest rate of 4.6%, the first column of mortgage payments applies. In that scenario, Buyer #1 buys Home A, #2 buys B, and #3 buys C. No one buys home D in this example. If interest rates rise by 2%, however, what happens?
Two possibilities exist here. The first is that all of these homes drop their prices significantly. For example, at a reduced price tag of about $525,000, buyer #1 would still be able to afford Home A at the higher interest rate. This is what the readers who objected to the reasoning in my earlier post think would happen. The family that initially owns Home A will still want to sell, so they'll have no choice but to accept a lower price because rates went up. The same goes for the other homes.
The other possibility, however, is that rising rates force buyers #1, #2, and #3 to settle for homes B, C, and D, respectively. In this case, perhaps the sellers decide they would rather not part with their homes at that deep of a loss. All three would have to take about a 20% hit. In some cases -- especially in today's housing market where equity levels are very low -- this would result in homeowners failing to break even on their home sale. Unless they have at least 20% equity, they would need to pay the bank some amount of money to sell their home or hope for a short sale.
Looking to History for Answers
So which scenario is it? To understand, we have to go beyond theory and look to what actually happens. I asked two economists who specialize in the housing market about what really occurs.
"The link between interest rates and home prices is empirically pretty weak at best," says housing economist Tom Lawler. His analysis is frequently featured on the popular Calculated Risk blog. Although some researchers have tried to link home prices to inflation-adjusted interest rates, the result have been "mixed and ambiguous," according to Lawler.
Yale economist and S&P/Case-Shiller Home Price Index godfather Robert Shiller agrees. "There is not a tight fit at all between the two: high mortgage rates do not translate automatically into low home prices," he says. In order to demonstrate his point, he provided the following data, which he compiled:
This shows Shiller's home price index and "long" interest rates, going back to 1890. The interest rates shown are not mortgage interest rates, because they are not available over this long period. Instead, long-term interest rates are shown, which he says tend to track mortgage interest rates. For example, the more recent data shows 10-year Treasury rates. So the rates curve doesn't show actual mortgage rates, but how they would have changed. As you can see, they didn't move in sync with home prices.
Yet Shiller also says that, in theory, rates could affect prices. He points, in particular, to the period around 1982. At that time, he notes that the Supreme Court ruled that mortgages could not be assumed by a new buyer. So with very high prevailing rates, many homeowners who had already locked in low interest rates could not afford to move. But that, in conjunction with the recession, still only pushed home prices down a little. This is the most salient story about interest rates and home prices in the last century, he says.