Landlords and property investors often ask, “do I need an accountant letter for a limited company mortgage?”—especially when exploring buy-to-let lending through a limited company structure. In 2025, this type of landlord mortgage is increasingly popular due to favourable taxation and flexibility in managing investment property finance. An accountant’s letter is often a key part of the mortgage application, helping lenders verify affordability, rental income, and financial stability. With limited company buy-to-let mortgages offering competitive interest rates and potential tax advantages, understanding the documentation requirements is essential. Whether you’re a first-time landlord or a seasoned portfolio investor, this guide explains everything you need to know.
Quick Facts
– Interest rates: 4.5% to 6.5% (subject to lender and applicant profile)
– Minimum deposit: 25%
– Rental coverage: 125% to 145% of mortgage interest
– Maximum loan-to-value (LTV): 75%
– Arrangement fees: Typically 1% to 2% of loan amount
– Application timeline: 4 to 8 weeks on average
In 2025, limited company buy-to-let mortgages remain a preferred route for landlords seeking tax efficiency and long-term growth. Lenders continue to assess affordability based on rental income and stress-tested interest rates. Accountant letters are often required to confirm company profit, director income, and ongoing viability.
How This Mortgage Works
A limited company buy-to-let mortgage is designed for landlords purchasing or remortgaging rental property through a special purpose vehicle (SPV) or trading limited company. The key difference from personal name mortgages is that the borrowing entity is the company, not the individual.
Most lenders require the company to be registered with Companies House and have SIC codes related to property letting or management. Interest rates are often slightly higher than standard BTL mortgage rates, but tax benefits can outweigh the cost difference.
Mortgage products include fixed-rate (2 to 5 years), variable, and tracker options. Fixed rates offer stability, while tracker mortgages may suit those anticipating interest rate drops.
This mortgage type suits portfolio landlords, higher-rate taxpayers, and those planning to grow a property portfolio. Lenders assess rental income, affordability, and company financials—often requesting an accountant’s letter to confirm figures.
Unlike residential mortgages, affordability is based on projected rental income rather than personal earnings. However, lenders may still assess the director’s financial background, especially for new companies or first-time landlords.
Eligibility and Criteria
To qualify for a limited company buy-to-let mortgage, applicants must meet specific lender criteria. While personal income is less critical, lenders still evaluate the financial health of both the company and its directors.
Income Requirements:
Most lenders don’t require a minimum personal income, but some prefer directors to earn at least £25,000 annually. An accountant’s letter may be requested to confirm director remuneration or retained profits.
Rental Coverage and Stress Testing:
Lenders use a rental coverage ratio of 125% to 145% of the monthly mortgage interest, stress-tested at 5.5% or higher. For example, if your mortgage interest is £1,000/month, your rental income must be at least £1,250 to £1,450.
Property Type Restrictions:
Standard buy-to-let properties (houses and flats) are generally acceptable. However, HMOs, student lets, and multi-unit freehold blocks may require specialist lenders and stricter criteria.
Credit Score Expectations:
A good credit history is essential. While lenders may be more flexible with limited company structures, adverse credit can limit options or increase interest rates.
Age and Employment:
Most lenders accept applicants aged 21 to 85, but some cap the age at the end of the mortgage term. Employment status is less relevant, but self-employed directors may need to show two years of trading history.
Portfolio Landlords:
If you own four or more mortgaged buy-to-let properties, you’re classed as a portfolio landlord. Lenders will assess your entire portfolio’s performance, including rental income, LTV, and stress-testing across all properties.
Limited Company vs Personal Name:
Limited company mortgages offer tax advantages, especially for higher-rate taxpayers. However, they come with additional costs and administrative requirements. Some lenders only lend to SPVs, while others accept trading companies.
Right-to-Rent and Licensing:
Landlords must comply with Right-to-Rent checks and local licensing rules. Mortgage lenders may request proof of compliance, especially in areas with selective licensing schemes.
Costs and Affordability
Limited company mortgages come with additional costs and affordability considerations. Understanding these is key to planning your investment.
Fees:
– Arrangement fees: Typically 1% to 2% of the loan
– Valuation fees: £300 to £1,000 depending on property value
– Legal fees: £800 to £2,000 for limited company structures
– Broker fees: £500 to £1,500 depending on complexity
Interest Rates:
Fixed rates offer stability, often ranging from 4.5% to 6.5%. Variable and tracker rates may be lower initially but can rise with Bank of England base rate changes.
Rental Income Calculations:
Affordability is based on rental income stress-tested at higher interest rates. Lenders may require a letting agent’s rental projection or existing tenancy agreements.
Tax Implications:
Limited companies can deduct mortgage interest as a business expense, avoiding the Section 24 restrictions that affect personal landlords. However, corporation tax applies to profits, and extracting income may incur dividend tax.
Insurance:
Lenders require buildings insurance and may insist on specialist landlord insurance covering liability, loss of rent, and legal expenses.
The Application Process
Applying for a limited company buy-to-let mortgage involves several stages. Working with a mortgage broker can streamline the process and improve your chances of approval.
Step-by-Step Process:
1. Research lenders and mortgage products
2. Set up an SPV limited company with appropriate SIC codes
3. Gather required documents (see below)
4. Submit application via broker or directly to lender
5. Property valuation and underwriting assessment
6. Receive mortgage offer and complete legal work
7. Finalise purchase or remortgage
Required Documentation:
– Accountant’s letter confirming company income and profit
– Company accounts (1-2 years preferred)
– SA302s and tax year overviews (if applicable)
– Director ID and proof of address
– Property details and rental projections
– Tenancy agreements (for remortgages)
Valuation and Survey:
Lenders instruct a valuation to confirm property value and rental potential. Some may also require a more detailed buy-to-let survey.
Timeline:
Applications typically take 4 to 8 weeks. Delays can occur if documentation is incomplete or if legal work is complex.
Broker vs Direct:
Using a specialist mortgage broker can help you access exclusive deals, navigate lender criteria, and avoid common pitfalls. Direct applications may be suitable for experienced landlords with simple cases.
Common Reasons for Rejection:
– Insufficient rental income
– Poor credit history
– Incomplete or inaccurate company accounts
– Non-compliant property (e.g. unlicensed HMO)
Benefits, Risks and Alternatives
Benefits:
– Tax efficiency through full mortgage interest deductibility
– Potential for higher borrowing based on rental income
– Easier portfolio expansion and property transfers
– Professional image and limited liability
Risks:
– Higher interest rates and fees
– More complex legal and accounting requirements
– Exposure to regulation changes (e.g. EPC rules, licensing)
– Void periods affecting cash flow
Alternatives:
– Bridging loans for short-term finance
– Commercial mortgages for mixed-use or semi-commercial properties
– Development finance for refurbishment or new builds
– Personal buy-to-let mortgages (if tax benefits are less relevant)
Remortgage vs Product Transfer:
Remortgaging can unlock better rates or release equity. Product transfers are quicker but may not offer the most competitive terms. Always compare options with a broker.
Frequently Asked Questions
What deposit do I need for a buy-to-let mortgage?
Most lenders require a minimum deposit of 25% for a limited company buy-to-let mortgage. Some specialist lenders may accept 20% if the rental income is strong, but this is rare. A larger deposit (e.g. 30-35%) can unlock better interest rates and improve affordability calculations.
Can I get a buy-to-let mortgage through a limited company?
Yes, many UK lenders offer buy-to-let mortgages to limited companies, particularly SPVs set up solely for property investment. Your company must be registered with Companies House and have relevant SIC codes. Lenders will assess the company’s financials and may require a personal guarantee from directors.
What rental coverage do lenders require?
Lenders typically require a rental coverage ratio of 125% to 145% of the monthly mortgage interest, stress-tested at 5.5% to 6.5%. For example, if your monthly mortgage interest is £1,000, your rental income must be at least £1,250 to £1,450. Some lenders apply lower stress rates for 5-year fixed products.
How does Section 24 tax affect buy-to-let mortgages?
Section 24 restricts mortgage interest relief for landlords holding property in their personal name, reducing net profits for higher-rate taxpayers. Limited companies are exempt from this and can deduct mortgage interest as a business expense, making limited company structures more tax-efficient for many investors.
Can I live in a property with a limited company buy-to-let mortgage?
No, you cannot live in a property financed with a limited company buy-to-let mortgage. These mortgages are strictly for investment purposes and require a tenancy agreement with third-party tenants. Living in the property would breach the mortgage terms and could lead to repossession.
What credit score do I need for a buy-to-let mortgage?
While there’s no fixed score, most lenders expect a good to excellent credit history. Missed payments, CCJs, or defaults can reduce your options or lead to higher interest rates. Some specialist lenders accept adverse credit, but terms may be less favourable. A mortgage broker can help match you with suitable lenders.
Key Takeaways