Subscription credit facilities are a common financing tool for investment funds, enabling borrowing against the unfunded capital commitments of investors. Historically, lenders required investor letters (also referred to as investor acknowledgment letters) from each investor or at least each borrowing base investor to directly confirm their obligation to fund capital calls for the benefit of the lender.
Over time, robust Limited Partnership Agreement (LPA) provisions in large, diversified funds have largely eliminated the need for such letters. However, in separately managed accounts (SMAs) and funds with concentrated investor bases, investor letters continue to serve a useful purpose by providing added clarity and direct confirmation of investor obligations.
This legal update examines the market’s shift away from investor letters in commingled funds and explores their continued relevance in SMAs and concentrated investor pools. It highlights how investor letters can offer additional contractual certainty through direct privity, mitigate potential fraud and credit risk, and clarify fund obligations.
In the early evolution of subscription credit facilities, lenders typically required investor letters from each investor to confirm the enforceability of capital call obligations.1 As the fund finance market matured, LPAs in large, institutional-grade funds began to include comprehensive lender protections – such as express authority to borrow and pledge commitments, binding investor obligations, waivers of defenses, and third-party beneficiary rights for lenders.
These built-in safeguards made it feasible for lenders to extend credit without separate investor letters, driven by efficiency and market demand. Requiring individual letters from numerous investors proved burdensome, particularly for large funds. By incorporating financing terms into LPAs – often negotiated upfront with anchor investors and in line with guidance from groups like ILPA – sponsors streamlined fund formation and enhanced credit facility readiness. Consequently, investor letters became largely unnecessary in funds with large investor pools.
While investor letters have become less prevalent in large, multi-investor funds, they remain a helpful tool in SMAs and funds with a concentrated investor base. As of 2025, market practice reflects a clear bifurcation: investor letters are generally not required for diversified funds but are often used where one or a few investors account for a significant portion of total commitments. Key scenarios include:
In summary, investor letters can supplement the LPA framework and provide additional assurance where lender exposure is more concentrated or complex.
A key function of investor letters is to provide clear and direct confirmation of certain investor obligations. Unlike reliance on LPA provisions, which may position the lender as a collateral assignee or third-party beneficiary subject to procedural hurdles, ambiguities and potential defenses, investor letters may help streamline enforcement by establishing a more direct line of privity, particularly in distressed scenarios or where LPAs are silent or ambiguous.
Beyond enhancing enforceability, investor letters may eliminate uncertainties found in fund documents and side letters by providing tailored confirmations that clarify key obligations. Typical provisions in an investor letter include:
These provisions not only reinforce the binding nature of the investor’s obligations but may also create an estoppel, preventing investors from later disputing their commitments. As a result, investor letters strengthen both the reliability of capital commitments as collateral and the overall enforceability of the lender’s rights.
Investor letters have also gained prominence as a fraud prevention and diligence mechanism. While subscription facilities have historically exhibited low default rates, high-profile fraud cases have prompted lenders to strengthen their verification protocols. In these cases, fund sponsors misrepresented investor commitments or misused capital call authority, inflating borrowing bases and circumventing traditional safeguards. Investor letters help verify commitments directly with the investor, serving as an important layer of fraud detection.
By requiring investor letters, lenders ensure:
While not a substitute for broader diligence, investor letters can complement practices such as capital call verification, investor funding history reviews, and spot checks.
While investor letters have become less common in large, diversified fund structures where LPA terms protect lenders, they offer meaningful benefits in SMAs, fund-of-ones, and concentrated investor pools. These letters provide direct enforceability, unambiguous commitments, and targeted risk mitigation – especially in high-exposure structures.
As diligence expectations rise and fraud awareness grows, investor letters are likely to remain an important component of fund finance transactions involving few or high-risk investors. They help align the interests of sponsors, investors, and lenders, fostering greater transparency and credit reliability. In today’s market, especially for concentrated deals, investor letters reaffirm an enduring principle in fund finance: it still pays to “trust but verify.”
1 For a detailed discussion on these provisions and model LPA provisions, see Model LPA Provisions for Subscription Credit Facilities.
2 For a detailed discussion on these provisions and model LPA provisions, see Model LPA Provisions for Subscription Credit Facilities.
Mayer Brown is a global legal services provider comprising associated legal practices that are separate entities, including Mayer Brown LLP (Illinois, USA), Mayer Brown International LLP (England & Wales), Mayer Brown Hong Kong LLP (a Hong Kong limited liability partnership) and Tauil & Chequer Advogados (a Brazilian law partnership) (collectively, the “Mayer Brown Practices”). The Mayer Brown Practices are established in various jurisdictions and may be a legal person or a partnership. PK Wong & Nair LLC (“PKWN”) is the constituent Singapore law practice of our licensed joint law venture in Singapore, Mayer Brown PK Wong & Nair Pte. Ltd. More information about the individual Mayer Brown Practices and PKWN can be found in the Legal Notices section of our website.
“Mayer Brown” and the Mayer Brown logo are the trademarks of Mayer Brown.
Attorney Advertising. Prior results do not guarantee a similar outcome.