Landlords and property investors seeking long-term stability in today’s volatile market are increasingly turning to a limited company buy to let mortgage accountant letter 10 year fixed. This type of mortgage is specifically designed for landlords purchasing or remortgaging investment properties through a limited company structure, offering a fixed interest rate for a full decade. Lenders often require an accountant’s letter to verify the company’s financial standing, especially when assessing affordability and rental income. In 2025, with interest rates stabilising after years of fluctuation, a 10-year fixed buy-to-let lending product offers predictable repayments and protection from future rate hikes. This makes it a popular choice for portfolio landlords and those planning long-term investment strategies. As taxation and regulation around landlord mortgage products continue to evolve, securing a fixed-rate investment property finance deal through a limited company can offer both tax efficiency and financial certainty.
Quick Facts
– Interest rates: 4.5% to 6.5% (2025 average for 10-year fixed BTL)
– Minimum deposit: 25%
– Rental coverage: 125% to 145% at 5.5% stress rate
– Maximum loan-to-value (LTV): 75%
– Arrangement fees: 1% to 2% of loan amount
– Application timeline: 4 to 8 weeks from submission to completion
In 2025, lenders remain cautious but open to limited company buy-to-let applications, especially from experienced landlords. Most lenders require a minimum 25% deposit and assess affordability based on projected rental income. Accountant letters are often essential for verifying company accounts, particularly for SPVs (Special Purpose Vehicles). A 10-year fixed rate provides long-term repayment certainty, shielding landlords from future interest rate rises.
How This Mortgage Works
A limited company buy to let mortgage accountant letter 10 year fixed is a specialist mortgage product designed for landlords purchasing or refinancing investment properties through a company structure. The “accountant letter” refers to a document prepared by a qualified accountant confirming the financial health of the limited company, often including details such as net profit, retained earnings, and confirmation of trading activity. This is a key part of the lender’s due diligence during affordability assessments.
The “10 year fixed” element means the interest rate is locked for a decade, providing consistent monthly payments regardless of market fluctuations. This appeals to landlords seeking long-term stability and protection against future interest rate increases. Mortgage types available include fixed, tracker, and variable, but fixed rates are particularly attractive in uncertain economic climates.
This mortgage suits portfolio landlords, SPVs, and investors seeking tax efficiency through a limited company structure. It differs from standard residential mortgages in that affordability is based on rental income rather than personal income, and underwriting is more complex. Lenders typically apply stricter stress tests and require more documentation, including company accounts and rental projections.
Eligibility and Criteria
To qualify for a limited company buy to let mortgage accountant letter 10 year fixed, applicants must meet specific lender criteria. While personal income is not the primary factor, some lenders still expect directors to demonstrate a minimum personal income (typically £25,000+) to ensure financial resilience.
Rental income is the cornerstone of affordability. Lenders use a rental coverage ratio, usually between 125% and 145%, stress-tested at an assumed interest rate of 5.5% or higher. For example, if the monthly mortgage payment is £600, the property must generate at least £750 to £870 in monthly rent depending on the lender’s criteria.
Property types must be standard buy-to-let properties. Some lenders exclude HMOs (Houses in Multiple Occupation), holiday lets, or new builds. Others may have preferences for freehold houses or leasehold flats with long leases.
Credit scores should be fair to excellent. While limited company applications focus on company finances, directors’ credit histories are still reviewed. Missed payments, CCJs, or defaults may impact eligibility.
Age limits vary, but most lenders require directors to be aged 21–75, with the mortgage term ending before age 85. Employment status is less critical for limited company applications, but self-employed directors may need to show trading history.
Portfolio landlords—those with four or more mortgaged properties—face additional scrutiny. Lenders may request a full portfolio spreadsheet, business plan, and evidence of rental income across all properties. (Read our guide to portfolio landlord mortgages)
Limited company applications must be made via an SPV or trading company, usually with SIC codes related to property letting. Personal name applications are assessed differently and may not benefit from the same tax advantages.
Right-to-rent compliance and landlord licensing are essential. Properties must meet local authority requirements, and landlords must ensure tenants have legal residency status.
Costs and Affordability
Costs for a limited company buy to let mortgage accountant letter 10 year fixed include several fees:
– Arrangement fee: typically 1% to 2% of the loan
– Valuation fee: £300 to £800 depending on property value
– Legal fees: £1,000 to £2,000 (more for limited company purchases)
– Broker fee: £500 to £1,500 depending on complexity
Interest rates for 10-year fixed BTL mortgages in 2025 range from 4.5% to 6.5%, depending on LTV, property type, and borrower profile. Fixed rates offer long-term affordability but may carry early repayment charges (ERCs).
Rental income is assessed using a stress test, often at 5.5% interest and 145% coverage. For example, a £200,000 loan would require rental income of around £1,330 per month.
Taxation is a key consideration. Limited companies are not subject to Section 24 mortgage interest relief restrictions, allowing full deduction of mortgage interest as a business expense. However, corporation tax and dividend tax apply, so landlords should seek specialist tax advice.
Insurance is mandatory. Lenders require buildings insurance, and landlord insurance is strongly recommended to cover liability, loss of rent, and legal expenses.
The Application Process
Applying for a limited company buy to let mortgage accountant letter 10 year fixed involves several steps:
1. Research the market or consult a mortgage broker to identify suitable lenders.
2. Prepare documentation: company incorporation certificate, accountant’s letter, business bank statements, property details, and rental projections.
3. Submit an application with a Decision in Principle (DIP).
4. The lender conducts a valuation and underwrites the application.
5. If approved, legal conveyancing begins, including company checks and property due diligence.
6. Completion typically occurs within 4 to 8 weeks.
Working with a mortgage broker can streamline the process and improve approval chances, especially for complex cases or portfolio landlords. Brokers have access to specialist lenders not available directly to the public.
Common reasons for rejection include insufficient rental income, poor credit history of directors, incorrect SIC codes, or inadequate documentation. Ensuring your accountant’s letter is accurate and up to date is crucial.
Benefits, Risks and Alternatives
The main benefits of a limited company buy to let mortgage accountant letter 10 year fixed include long-term interest rate stability, tax efficiency, and enhanced affordability calculations based on rental income rather than personal income.
However, risks include void periods (when no rent is received), potential interest rate rises after the fixed term, and regulatory changes affecting landlord obligations. Early repayment charges can also be significant if you exit the mortgage early.
Alternatives include:
– Bridging loans for short-term finance
– Commercial mortgages for mixed-use or semi-commercial properties
– Development finance for refurbishment or new builds
Remortgaging at the end of the fixed term may offer better rates, but some landlords opt for product transfers with the same lender to avoid legal costs and underwriting. (Read our guide to remortgaging a buy-to-let property)
Frequently Asked Questions
What deposit do I need for a limited company buy-to-let mortgage?
Most lenders require a minimum deposit of 25% for limited company buy-to-let mortgages. Some may accept 20% for low-risk applicants, but 25% is the standard threshold. For specialist properties or first-time landlords, a higher deposit of 30% to 40% may be required. The deposit must come from the company or directors, and lenders may ask for proof of source of funds.
Can I get a limited company buy to let mortgage accountant letter 10 year fixed through a limited company?
Yes, this mortgage is specifically designed for limited company structures. The lender will assess the company’s financials, often requiring an accountant’s letter to confirm income, trading history, and retained profits. The company must be registered with appropriate SIC codes (e.g., 68209 for property letting). Directors usually provide personal guarantees.
What rental coverage do lenders require?
Lenders typically require a rental coverage ratio of 125% to 145%, stress-tested at an interest rate of 5.5% or higher. For example, if your mortgage payment is £800 per month, your rental income must be between £1,000 and £1,160. Limited company applications may benefit from lower stress rates due to tax treatment differences.
How does Section 24 tax affect buy-to-let mortgages?
Section 24 restricts individual landlords from deducting mortgage interest from rental income. This increases taxable income and potentially pushes landlords into higher tax bands. Limited companies are exempt from Section 24, allowing full interest deduction as a business expense. This is a key reason many landlords now use limited company structures.
Can I live in a property with a limited company buy to let mortgage accountant letter 10 year fixed?
No, you cannot live in a property financed with a buy-to-let mortgage. These mortgages are strictly for rental purposes. Living in the property would breach the mortgage terms and could lead to repossession. If you plan to reside in the property, you must apply for a residential mortgage instead.
What credit score do I need for a buy-to-let mortgage?
While there is no fixed minimum score, lenders typically look for a fair to excellent credit rating. Directors with recent CCJs, defaults, or missed