Four major lenders have announced price rises effective today or tomorrow (Mortgage Finance Gazette, 25 March 2026). Increases of up to 50 basis points (hundredths of a percentage point) hit buy-to-let (BTL) investors hardest. Newcastle Building Society is also withdrawing a long list of products at close of business with no relaunch date - a move that typically signals deeper repricing ahead.

Who's Moving and When

TSB is raising rates across remortgage products tomorrow. Two-year fixed BTL rates are up 45 basis points, five-year fixes by 25 basis points, and three-year residential deals by 30 basis points (Mortgage Finance Gazette, 25 March 2026).

Principality Building Society's increases hit hardest on high loan-to-value (LTV) deals (effective tomorrow). Two-year fixes at 90% LTV jump 50 basis points. Shared ownership two-year fixes and 85% LTV products also move up 50 basis points, with other product transfers rising 25 to 45 basis points.

NatWest is implementing 15 basis point increases across most products tomorrow.

Metro Bank is withdrawing its entire product range today at 5:30 p.m. to implement increases across residential and buy-to-let mortgages. Nottingham Building Society and Coventry have also announced rises today.

What This Costs You

Run the numbers on a typical buy-to-let scenario. A £150,000 interest-only mortgage at 5% fixed costs £625 per month. If that rate rises 50 basis points to 5.5%, your monthly payment jumps to £687.50. That's an extra £62.50 every month for two years - £1,500 extra over the full term.

Here's the working: At 5%, you pay £150,000 × 0.05 / 12 = £625/month. At 5.5%, that's £150,000 × 0.055 / 12 = £687.50/month. The difference is £62.50 × 24 months = £1,500.

This matters because many BTL investors are remortgaging now ahead of higher rates. If you're mid-application or your deal lock is expiring within days, every basis point counts. Lenders are repricing in clusters - when one moves, others follow within hours.

The Newcastle Signal

Newcastle's withdrawal of scores of products with no relaunch timeline is significant. Lenders do this when they're either repricing substantially or pausing lending. Given today's repricing wave, the most likely explanation is that Newcastle is pricing more aggressively and needs a clean break to implement system updates.

This isn't panic. But it confirms the pattern: lenders are tightening margins on residential and BTL simultaneously.

What to Do Now

If you're in an active application, consider speaking to your broker today. Your rate lock may still be valid, but only if you lock before these increases take effect. You may want to check the exact time you locked in and the exact time the lender's pricing update goes live. Five minutes can make a difference.

If your remortgage deal expires within 30 days, you may wish to submit your application before close of business today. Tomorrow's pricing is likely to be higher than today's, and the week ahead will probably see more moves.

If you're evaluating buy-to-let yields, consider stress-testing against 5.5% rather than today's rates. The repricing pressure is clearly upward.