Why BNG matters to lenders
If you provide development finance in England, BNG is now a material consideration in your lending decisions. Since February 2024, virtually every development your borrowers undertake must demonstrate a 10% biodiversity net gain before construction can commence. This introduces new costs, new risks, and new asset classes into the development finance landscape.
The impact depends on who your borrower is and how they plan to deliver BNG. This guide covers both sides of the lending relationship: financing developers who must comply with BNG, and financing landowners who are creating habitat banks to supply the BNG market.
Lending to developers: the risk framework
When your borrower is a property developer, BNG introduces several risk factors that should be assessed as part of your due diligence process.
On-site BNG delivery
The developer creates or enhances habitats within the development site boundary. This is the lowest-risk position for lenders because the borrower and their professional team have full control over delivery and ongoing maintenance. The management obligation runs with the land, so at final disposal the obligations transfer to the new owner.
Off-site units (private market)
The developer purchases biodiversity units from a registered habitat bank. This introduces an additional cost (typically £20,000–£35,000 per unit) but the delivery and 30-year management liability sits with the habitat bank operator, not the developer. If units are purchased from a reputable operator who fully pre-funds management, this can provide a clean break.
Statutory credits (government scheme)
The developer purchases statutory credits from the government as a last resort. This is the most expensive route — starting at an effective £84,000 per unit (with the 2x spatial risk multiplier). It signals that the development has high BNG costs and that on-site and off-site options were insufficient.
Due diligence checklist
The following questions should be incorporated into your development finance due diligence process:
Pre-application / site acquisition stage
- ☐Has the borrower obtained a preliminary ecological appraisal of the site?
- ☐Does the site contain any Very High distinctiveness or irreplaceable habitats (ancient woodland, blanket bog, etc.) that could trigger bespoke compensation requirements?
- ☐Has BNG been factored into the land acquisition appraisal and development budget?
- ☐Is the site in an LPA area with registered habitat banks (i.e., can off-site units be sourced locally if needed)?
- ☐Is the development potentially exempt from BNG under current or forthcoming rules (e.g., site under 0.2 hectares)?
Planning / pre-commencement stage
- ☐Has the borrower completed the Statutory Biodiversity Metric calculation?
- ☐What is the unit shortfall after maximising on-site delivery? What tier(s) are needed?
- ☐What is the borrower's BNG strategy — on-site, off-site, credits, or a combination?
- ☐If off-site units are needed, have they been sourced and are they from a registered gain site?
- ☐Has the Biodiversity Gain Plan been approved by the LPA (this is a pre-commencement condition)?
- ☐What are the total BNG compliance costs and how are they funded within the facility?
Post-completion / ongoing
- ☐Who is responsible for 30-year on-site habitat management — the borrower, a management company, or will it transfer to purchasers?
- ☐If sub-contracted to a managing agent, is a duty of care deed to the lender required?
- ☐Has the borrower built management costs into service charges or an endowment?
- ☐What happens to the BNG obligation on exit — does the management obligation transfer cleanly to the buyer?
Lending to landowners: habitat bank finance
BNG has created a new asset class: biodiversity units generated from habitat creation on agricultural or degraded land. Landowners are increasingly seeking finance to acquire land and fund habitat bank creation — and innovative lenders are beginning to serve this market.
Key considerations for habitat bank lending
- Revenue model: Income comes from unit sales to developers. The borrower needs to demonstrate local demand (are there developments nearby that need off-site units?) and a credible pricing strategy.
- 30-year obligation: The land is legally committed to habitat management for at least 30 years. During this period, it generally cannot be used for agriculture or other income generation. This significantly affects loan-to-value ratios and exit strategies.
- Capital vs income assessment: The capital sum from unit sales must be weighed against the loss of 30+ years of agricultural or alternative income from the land.
- Pre-funding management: Best-practice habitat bank operators pre-fund the full 30-year management cost at the point of unit sale. Check whether the borrower's financial model includes this.
- Legal security: The land will be subject to a conservation covenant or S106 agreement. Understand how this affects your security position.
- Market risk: The BNG unit market is still nascent. While demand is growing (mandatory since 2024, NSIPs from May 2026), there are geographic variations in supply and demand.
- Ecological delivery risk: Not all habitat creation succeeds. Insurance products are emerging to mitigate this, but the risk should be understood and priced.
BNG cost impact on development viability
Understanding the typical cost impact of BNG helps lenders assess borrower viability:
| BNG route | Typical cost impact | Viability implication |
|---|---|---|
| On-site delivery (well-designed) | 1–3% of total project cost | Manageable within most development margins; should be in the original appraisal |
| Off-site units (moderate shortfall) | £20k–£35k per unit; 2–5% of GDV for typical housing | Significant but predictable; check it's included in the drawdown schedule |
| Statutory credits (significant shortfall) | £84k+ per unit; can exceed 10% of GDV | Material viability risk; stress-test the appraisal with full credit costs |
| Very High / irreplaceable habitats | Bespoke — can be project-defining | Potential deal-breaker; requires specialist ecological and legal assessment before lending |
The opportunity: green and sustainable finance
BNG isn't only a risk factor — it also creates lending opportunities:
- ESG alignment: BNG lending naturally fits environmental, social, and governance frameworks, supporting sustainable lending commitments
- Green loan products: Favourable terms for developments that exceed the 10% BNG minimum could attract environmentally conscious developers and provide differentiation
- Habitat bank financing: A new lending vertical serving the growing habitat bank market — as demonstrated by the Triodos/Nature Impact transaction
- Nature-positive portfolios: Understanding BNG exposure across a lending portfolio enables better ESG reporting and risk management
- Advisory services: Lenders with BNG expertise can offer value-added advisory to borrowers, strengthening relationships
The Green Finance Institute has convened over 100 stakeholders to develop a BNG Roadmap for Action, highlighting the need for innovative finance models to support BNG delivery at scale.
2026 reforms: what lenders should watch
- 0.2 hectare exemption (late 2026): Will reduce BNG compliance requirements for many small sites in your portfolio — reducing cost risk for those borrowers
- NSIP mandate (May 2026): Creates new BNG obligations for major infrastructure — relevant if you finance large-scale projects
- Brownfield exemption (under consultation): Could remove BNG costs for residential brownfield up to 2.5ha — significant for brownfield-focused housebuilders in your portfolio
See our full 2026 reforms guide for details on all changes.