We use administrative data covering the universe of mortgage originations to individ- ual real estate investors in the United Kingdom to study financing outcomes following a large, unanticipated increase in interest rates. Post-shock, originations become more concentrated among specialist lenders, who exhibit lower rate pass-through for larger borrowers. To offset these smaller rate increases, they charge higher loan fees, thereby attenuating the impact of higher rates on interest-coverage ratios. High-frequency data on the menu of loans on offer show similar responses, indicating that specialist lenders adjust product design to target specific borrower types and, in doing so, reinforce market segmentation.