Big Shift Toward 5.0 Coupons Continues

Mortgage rates have lurched rapidly lower in September as 5.0 UMBS have stolen the show from 5.5 UMBS. As a reminder, there is only a certain range of rates allowed in either bucket. 5.5s go all the way up to 6.625% and investors buying MBS would prefer not to get stuck holding a burning bag of 6.625% loans in a market where those borrowers are already on the edge of being in the money on a refi. Bottom line, it's the fastest/biggest shift in 5.0 outperformance since late 2023, and today's installment brought the spread between the two coupons to the tightest levels since early October 2024.  Lo and behold, that's the last time rates were in this territory. Spreads spiked back to wider levels on October 4th owing to a strong jobs report. This October's jobs report will be in focus for similar reasons, but before that, near-term volatility risks surround Wednesday's Fed dot plot.