BTL Mortgage Rate Cuts: Should You Refinance in May 2026?

Buy-to-let mortgage rates have turned. The Mortgage Works repriced a two-year fixed buy-to-let to 3.32% at 75% loan-to-value in the week ending 15 May 2026, with HMO and multi-unit rates from 4.29%. The Mortgage Lender cut its standard BTL fixed rates by up to 35 basis points across two- and five-year products. The Bank of England held base rate at 3.75% on 30 April 2026, with the Monetary Policy Committee voting 8-1 to hold (one member voted to raise to 4%). Two-year swap rates have fallen roughly 50 basis points since early April. The result is the first proper window of cheaper buy-to-let credit since rates surged in mid-2024. If you are a UK landlord with a fix maturing in the next nine months, the refinance maths matters now in a way it did not in March.

The short version. Cheaper rates do not automatically mean refinance now. The decision splits on three numbers: your early repayment charge, your remaining fix term, and the gap between your current rate and what is available today. Get those three right and you can save five figures across the next fix. Get them wrong and you pay a six-month exit penalty to capture a rate that fell another quarter point eight weeks later. The 90-day window from late May to late August 2026 is when most landlords will need to make this call, because that is when product pipelines and offer validity periods align with autumn completions.

What just happened to BTL mortgage rates in May 2026?

The rate cuts came in two distinct waves. The Mortgage Lender moved first in the second week of May, cutting two- and five-year BTL fixes by up to 35 basis points and relaunching 75% LTV products that had been pulled in February. Standard single-let buy-to-let starts at 4.14%. HMO and multi-unit blocks start at 4.29%. The Mortgage Works followed within a week, repricing across one-, two- and five-year fixes by up to 20 basis points and adding a new two-year tracker at 4.19% for 75% LTV. Paragon, Aldermore and Foundation Home Loans repriced sections of their range in line, with focused cuts on portfolio landlord products.

The fall is sharper at the bottom of the LTV range. A 60% LTV two-year fix is now available below 3.5% at multiple lenders. At 75% LTV, the cheapest two-year fixes sit in the 3.3% to 3.6% band on smaller arrangement fees and 4.0% to 4.4% on percentage fees, depending on the lender's pricing logic. Five-year fixes hover around 4.2% to 4.5% for 75% LTV vanilla BTL. That is roughly 80 to 110 basis points lower than where the same products priced in October 2025, before swap rates spiked on the Middle East energy shock.

The pricing is real but the volumes are modest. Lenders are using rate cuts to refill pipelines, not to win the market outright. Most of the cheapest products carry a 3% arrangement fee, which adds roughly 1.5 percentage points to the true cost on a two-year deal. The headline rate sells the product. The total cost of credit is what matters when you build the spreadsheet.

Why are lenders cutting now while base rate stays at 3.75%?

BTL mortgages price off swap rates, not directly off Bank of England base rate. The two-year swap rate fell from around 4.1% in early April 2026 to about 3.6% by 15 May, a 50 basis point move in six weeks. Five-year swaps moved similarly. Lenders that hedged their pipelines at the lower swap level can offer cheaper fixes without squeezing their margin. The lenders that hedged earlier at the April peak are watching pipeline conversion fall and either repricing or losing market share. Either way, the consumer wins.

Swaps moved because the bond market repriced the Bank of England's likely path. The MPC's 8-1 vote on 30 April was hawkish on paper, but the language in the meeting minutes pointed to "increased confidence" in disinflation, which the gilt market read as preparation for cuts later in 2026. Two cuts of 25 basis points each by March 2027 are now the modal market expectation. The swap market does not wait for the cuts to actually happen. It prices them in once probability tips over 50%.

The risk is real that the cuts reverse. Two-year swaps could move 30 to 40 basis points in either direction inside a fortnight if inflation surprises higher or a geopolitical shock revives the energy story from late 2024. Read our piece on why mortgage rates spiked in early 2026 for the context on how quickly the picture inverted. The current cuts are not a one-way bet.

Should you break your existing fix to lock in a lower rate?

The answer depends on three numbers: the early repayment charge (ERC) on your existing fix, the remaining term, and the saving you would capture on a new product.

Run a quick worked example. You hold a £200,000 BTL mortgage at 5.79% on a five-year fix with 18 months remaining. The ERC is 3% in year four, 2% in year five. You sit in year four, so the ERC is £6,000. New arrangement and valuation fees on a replacement fix are roughly £2,500. A five-year fix at 4.35% is on offer. The 1.44 percentage point saving on £200,000 across 18 months is £4,320. After paying £6,000 ERC and £2,500 of new fees, you are £4,180 worse off across the remaining 18 months of the old deal. The new fix then starts and runs five years at the lower rate, so the long-term picture might still work, but the cash hit is real.

The maths flips when the ERC is small or the gap is bigger. If your ERC is 1% in the final year of the fix, the £6,000 in the example above falls to £2,000, and breaking early shows a net positive almost immediately. Equally, if you sit on a 6.5% reversion rate having dropped off a fix, switching to a 4.35% deal saves you 2.15 percentage points from day one with no ERC at all. That is the easy decision.

The rule of thumb. Break only if you sit inside the ERC-free window (typically the last three to six months of the fix), if your ERC is at the 1% to 2% end rather than 3% to 5%, or if you have already dropped onto a high reversion rate. Otherwise, sit tight and watch where rates sit when your fix matures.

What does the maths look like for a typical landlord remortgaging in 2026?

The cleaner decision faces landlords whose fix matures between July 2026 and February 2027. You can normally apply for a new product six months ahead of completion and lock the rate at offer. That means landlords with a maturity in November 2026 can lock today at the May 2026 pricing.

Take a £150,000 BTL loan at 75% LTV on a £200,000 property. Coming off a 4.99% fix at maturity, your monthly interest-only payment is £624. Refixing at 4.35% drops that to £544, saving £80 a month or £960 a year. Across a five-year fix, that is £4,800 of saved interest. The arrangement fee on a typical 3% product is £4,500, which almost cancels the saving. Switch to a £999 flat fee fix at 4.65% and the monthly payment is £581, saving £43 a month or £516 a year. Across five years that is £2,580 of saved interest after a £999 fee, a net £1,581 ahead.

The arrangement fee structure now matters more than the headline rate for most landlords. Run the total-cost-of-credit calculation on every offer, not just the rate. A BMV deal analyser calibrated for UK BTL pricing can model the full cost across the fix term in under a minute, with sensitivity to rent voids and the Section 24 tax position.

Where are the catches in the new BTL fixed rates?

Three traps to watch. First, the cheapest rates are available only to landlords with a strong personal credit file and a clean six months of rental income on existing properties. New investors building a first portfolio face a tighter range and 0.4 to 0.6 percentage points higher pricing. The "from 3.32%" headline is not the rate most first-time landlords will see.

Second, limited company BTL pricing has moved less than personal-name pricing. Special purpose vehicle (SPV) lenders like Paragon and Foundation cut by 10 to 20 basis points across May, but the structural premium of 30 to 50 basis points over personal-name BTL remains. With four out of five new buy-to-let purchases now going through a Ltd company, that gap matters. Read our limited company BTL piece for the post-tax maths showing why most higher-rate landlords still prefer the SPV route despite the rate gap. A structure comparison tool with your actual numbers shows whether the SPV route still beats personal name after the May rate cuts.

Third, stress tests have tightened in parallel with the rate cuts. Lenders now stress affordability at pay rate plus 1 percentage point for five-year fixes and pay rate plus 2 percentage points for two-year fixes. On a 4.35% five-year fix, that is a stressed rate of 5.35%. The Interest Coverage Ratio (ICR) requirement of 125% for basic-rate taxpayers and 145% for higher-rate taxpayers applies at the stressed rate, not the actual rate. That ICR test is what blocks roughly 18% of refinance applications in 2026, even when the borrower can clearly afford the actual payment.

How to make the refinance decision in under an hour using AI

The refinance decision used to mean a broker call, a spreadsheet evening, and a 10-day wait. The AI shortcut is faster but only works if you feed it the right inputs. Pull these numbers before you start. The current loan balance and rate. The ERC schedule (your annual statement shows it). The fix maturity date. The current rental income, gross. Your most recent Self Assessment tax return or company accounts. The property's current estimated value.

Feed those into ChatGPT, Claude or Perplexity with a prompt like "I have a £200,000 BTL fix at 5.49% maturing in 14 months, 2% ERC, rental income £1,400 per month, basic-rate taxpayer, property valued at £270,000. Should I refix now or wait? Show the maths." The response in 2026 is credible across all three. It will normally suggest waiting because the ERC eats the saving. Then ask it to model the same decision if rates fall another 30 basis points by August, and if rates rise 30 basis points by August. The two-scenario answer gives you the actual decision framework: wait if you think rates hold or fall, refix early only if you think rates spike before maturity.

The catch. AI models pull from public lender pricing that lags actual broker access by two to four weeks. The 3.32% Mortgage Works deal will not show up in an AI search until at least early June. Use AI to model the decision logic, then call a broker for the specific product. A portfolio growth planner calibrated for UK BTL refinance economics handles the multi-property case where 18 different mortgages mature across 24 months, which is where the manual approach breaks down. Read our AI for property investment piece for the broader toolkit.

The 90-day window UK landlords cannot afford to miss

The window from late May to late August 2026 is when most landlords with autumn-maturing fixes can lock current pricing. Miss it and you complete in October or November at whatever rates exist then. If swaps continue down 20 to 40 basis points, waiting captures the extra saving. If swaps spike on an inflation surprise or geopolitical event, locking now captures the May pricing. The probability-weighted bet for most landlords sits with locking, because the downside of a 30 basis point rise hurts more than the upside of a 30 basis point fall on the same loan.

For landlords with a portfolio approaching the exit decision, the refinance call is also a hold-or-sell call. Locking five years at 4.35% commits you to the property through 2031, with ERCs to break early. If you are unsure about staying in BTL given the Renters' Rights Act regime, a two-year fix at 4.5% to 4.7% buys flexibility at the cost of 30 to 40 basis points of rate. That premium is roughly £600 a year on a £200,000 loan, which is a small price for optionality if you are genuinely unsure.

The bottom line. Rates have moved enough to change the maths for many landlords, but not enough to justify breaking expensive fixes. Lock now if your fix matures inside 12 months and you have a clear hold plan. Watch and wait if your ERC is 3% or higher. Either way, run the numbers properly. The cost of the wrong call across a five-year fix on a portfolio sits in five figures.