Prospective homebuyers priced out of the booming housing market are flocking to rentals as a flexible and more immediately affordable alternative. Unfortunately, prices are soaring there as well.

Asking rents for single-family homes jumped nearly 13 percent year-to-date through the end of July, the highest such increase in five years, the Wall Street Journal reported, citing data from research firm Yardi Matrix.

Multiple factors are contributing to the spike. Joining those unable to buy homes are city residents who opted to rent in the suburbs while waiting out the pandemic, further driving demand.

Additionally, fewer homes are being built and put on the market for both buyers and renters, further hamstringing supply. Housing starts dropped 7 percent month-over-month in July, falling short of expectations as builder confidence hit a 12-month low.

The price increases are accelerating. Asking rents for single-family homes increased 7.2 percent year-over-year in March, 8.6 percent in April, 10.5 percent in May, 12.2 percent in June, and 12.8 percent in July, according to Yardi data.

Including renewals, rents for all single-family homes nationwide spiked 7.5 percent year-over-year in June, according to data from CoreLogic, the highest annual increase recorded in at least 15 years.

Investors are taking notice, with alternative asset managers and private equity firms including Blackstone and KKR injecting billions into the market this year alone.

Apartment asking rents have increased this year as well, although less dramatically. They’re up 8.3 percent nationwide since the start of the year, according to Yardi. Single-family tenants renewing their leases are also seeing prices rise, but not to the same extent as new asking rents, the Journal reported.