Mortgage rates moved up over the past week to 4.66 percent, their highest level since May 5, 2011 (4.71 percent).

Mortgage rates so far in 2018 have had the most sustained increase to start the year in over 40 years. Through May, rates have risen in 15 out of the first 21 weeks (71 percent), which is the highest share since Freddie Mac began tracking this data for a full year in 1972.

At a time when housing inventory remains extremely low, it’s worth watching whether these higher borrowing costs lead some would-be sellers to stay put in their current home. Inventory shortages would likely worsen if more homeowners decide not to sell out of reluctance of having a new mortgage with a higher rate.