Co-Investment Vehicles and Side Letters in Cayman Fund Structures

This article examines the structural frameworks used to accommodate co-investment in Cayman-domiciled funds, the contractual and documentary foundations that govern co-invest vehicle formation and operation, the application of side letters and MFN provisions to co-investment scenarios, and the regulatory treatment of co-invest vehicles under the Private Funds Act 2020. The focus is on the tensions between investor protection, GP operational flexibility, and regulatory compliance.

Drivers and Commercial Rationale for Co-Investment Structures

Co-investment has become ubiquitous in institutional PE as investors seek to increase their exposure to the most attractive portfolio companies while reducing their overall asset base subject to management fees. A typical institutional LP might deploy 50 to 70 per cent of its targeted fund capital to the main fund (paying full management fees and carry) and reserve 20 to 50 per cent for direct co-investment in the fund's portfolio companies (paying limited or no management fees). For the investor, this creates a significant fee saving on a portion of its capital while maintaining exposure to the GP's deal flow and investment thesis.

From the GP's perspective, co-investment presents both strategic advantages and operational complexity. Permitting LPs to co-invest alongside the main fund demonstrates confidence in the GP's ability to source strong deals and strengthens investor relationships by allowing LPs to participate more fully in upside. Moreover, co-investment from LP capital reduces the amount of GP capital that must be committed to the fund, lowering the GP's aggregate commitment and leverage while still achieving the target fund size.

However, the co-investment opportunity creates tensions and conflicts. If the main fund and the co-invest vehicle compete for available capital in a particularly attractive deal, which entity should have priority? If a co-invest vehicle achieves exceptional returns on one investment while the main fund underperforms on others, do co-invest investors have an obligation to "crossover" and contribute to follow-on rounds in lower-performing portfolio companies? How are transaction fees (deal sourcing, structuring, and advisory fees) allocated between the main fund and co-invest vehicles? These questions are addressed through careful contractual documentation and governance mechanisms, but ambiguities create substantial dispute risk.

Co-Invest Vehicle Structures: SPVs, Parallel Vehicles, and Feeder Arrangements

Three principal structures accommodate co-investment in Cayman-domiciled funds: special purpose vehicles (SPVs) dedicated to each portfolio company, parallel vehicles that hold proportional interests alongside the main fund across multiple deals, and feeder arrangements in which the co-invest vehicle is a separate fund alongside the main fund.

SPV Structures

The SPV structure is the simplest and most common in early-stage PE and venture capital. For each portfolio company in which co-investment is available, the GP establishes a dedicated Cayman exempted company that serves as the investment vehicle. The main fund invests in the SPV, and co-investors subscribe directly to the SPV alongside the main fund. The SPV is typically established as a single-class share company with investor pro-rata rights based on share ownership. The benefit of the SPV structure is its simplicity: each deal is independently structured, and investors in the SPV are subject to a simple governance framework (share register, directors' resolutions, shareholder voting rights) without the complexity of a master LPA or waterfall mechanics. However, the SPV structure creates administrative overhead if a fund has many portfolio companies, as each SPV requires separate formation, administration, and tax reporting.

Parallel Vehicle Structures

The parallel vehicle structure is used in larger PE funds where the GP wishes to consolidate co-investment across multiple deals within a single dedicated vehicle. The parallel vehicle (typically a Cayman exempted company or exempted limited partnership) is structured in parallel to the main fund: it has a similar (but not identical) LPA or articles, covering the same investment period and the same portfolio companies. The main fund and the parallel vehicle negotiate a co-investment agreement that specifies the mechanics of participation in each investment opportunity. Typically, each co-invest opportunity is offered to the parallel vehicle on a pro-rata basis (the parallel vehicle can invest up to a specified percentage of the main fund's investment, say 30 or 50 per cent), and the two vehicles invest via separate share subscriptions in each portfolio company SPV or via directly held equity or debt interests.

The parallel vehicle structure offers economies of scale and simplifies administration across multiple deals. However, it requires careful documentation to address the relationship between the parallel vehicle and the main fund, the mechanics of capital calls and distributions, and the governance of decisions affecting both vehicles. Moreover, parallel vehicle LPAs must specify whether limited partners in the parallel vehicle are entitled to participate in follow-on funding rounds (a common source of dispute) and whether the parallel vehicle is obligated to participate in secondary transactions or GP-led continuation vehicles affecting the main fund's portfolio.

Feeder Fund Structures

The feeder structure treats co-investment as a separate fund with a separate LPA, investor base, and capital account. Unlike a parallel vehicle, which co-invests alongside the main fund but typically has similar governance and investment criteria, a feeder structure creates a dedicated co-investment fund that may have different management fees (often lower, or none), different carry arrangements, and different investor preferences. Feeder funds are often used when a GP wishes to raise institutional capital that is specifically earmarked for co-investment and when the feeder fund will have a distinct investor base (e.g., dedicated secondary fund investors or a single large strategic LP) with bespoke terms.

Fee and Carry Arrangements: Allocating Economics Between Main and Co-Invest Vehicles

Management Fee Allocation

The allocation of management fees and carried interest between the main fund and co-invest vehicles is one of the most heavily negotiated elements of co-investment structures. The baseline principle is that the main fund should recover its management fees from capital supporting the main fund's proportional ownership, while co-investors should not pay management fees on capital deployed through co-invest vehicles.

For the main fund, management fees are typically calculated on committed capital (at the outset of the fund) or on invested capital (based on actual capital deployed) or on a hybrid basis. If a main fund has committed capital of $500 million and actual invested capital of $400 million, the fee base might be the committed amount ($500m), the invested amount ($400m), or a combination. The inclusion of co-invest vehicles in the fee calculation is contentious: if an LP commits $100 million to the main fund and simultaneously commits $30 million to a parallel co-invest vehicle, should the main fund's management fee be calculated on the full $100 million LP contribution, or should it be reduced by the LP's co-invest commitment?

ILPA market principles recommend that management fees on the main fund be calculated on capital deployed to the main fund only, excluding co-investment commitments. This approach prevents the GP from effectively double-counting investor capital for fee purposes. Accordingly, an LP committing $100 million to the main fund and $30 million to the co-invest vehicle would pay main fund fees only on the $100 million and would pay reduced or no fees on the $30 million co-invest capital.

Carried Interest and Transaction Fee Allocation

Carried interest allocation between main fund and co-invest vehicles presents similar issues. The carried interest earned by the GP on the main fund is calculated based on the main fund's profit waterfalls. Co-invest vehicles typically have reduced or no carried interest, reflecting the fact that co-investors are bearing investment risk alongside the GP without an intermediary GP. In some structures, the co-invest vehicle provides carried interests to GPs and employees with meaningful equity stakes, but at a lower rate (e.g., 10 per cent co-invest carry vs. 20 per cent main fund carry) to reflect the reduced asset management burden.

The transaction fees (deal sourcing, structuring, investment advisory fees charged to portfolio companies) also require careful allocation. A common approach is for transaction fees to be charged by the main fund (as the entity undertaking deal sourcing and structuring), with the transaction fees paid by the portfolio company allocated proportionally to the main fund and co-invest vehicles based on their respective equity investments. Alternatively, transaction fees may be charged only to the main fund, with co-invest vehicles bearing the benefit of deal sourcing without fee liability (an investor-friendly approach).

Currency and timing mismatches between main fund and co-invest vehicle capital calls can create cash flow issues. If the main fund and a parallel co-invest vehicle each subscribe for 50 per cent of a portfolio company, but the main fund's capital call is due within 5 days while the co-invest vehicle's call is due within 30 days, the portfolio company may face timing mismatches in capital availability. Most documentation addresses this by requiring that capital calls to co-invest vehicles follow within a specified period (typically 5 to 10 days) of main fund calls, ensuring synchronized capital deployment.

Side Letters, MFN Provisions, and Co-Investment Rights Documentation

Side Letter Mechanics

Co-investment rights are typically addressed through side letters (also called "lettres de souhait" in some jurisdictions) rather than through amendments to the main fund LPA. A side letter is a bilateral agreement between the GP and a specific LP that grants the LP certain rights or exemptions from LPA terms. Side letters commonly grant co-investment rights, exemptions from management fees on co-invest capital, specific reporting or governance rights, and key person protections.

The structure of a side letter granting co-investment rights typically provides that the LP has the right (but not the obligation) to participate in co-investment opportunities in specified portfolio companies. The side letter defines what constitutes a "co-investment opportunity" (typically defined as an investment in a portfolio company held by the main fund, with minimum investment thresholds to avoid administrative burdens of micro-investments). The side letter specifies the mechanics of the co-invest right: the LP must commit co-invest capital (and specify the maximum aggregate commitment), the co-invest capital will be deployed via a designated co-invest vehicle (SPV, parallel vehicle, or feeder fund), and the LP's return on co-invest capital will be calculated on a separate basis from main fund returns.

MFN Provisions and Interpretation Challenges

MFN (most-favoured-nation) provisions in side letters create significant complexity and potential disputes. An MFN provision obligates the GP to grant to the recipient LP no less favourable terms than offered to any other LP. An MFN on co-investment rights might provide that if the GP offers any other LP a co-invest opportunity in a particular deal, the recipient LP (the MFN beneficiary) must be offered the same opportunity on identical or substantially identical terms. MFN provisions often include carve-outs for specific, named LPs or for LPs with specific characteristics (e.g., "strategic LPs" or "founder investors"), which permits the GP to provide preferential co-invest terms to certain investors without triggering MFN obligations.

The ILPA Principles on side letters (published in 2018 and updated periodically) recommend that side letters not contain terms that would cause an LP receiving side letter benefits to be treated less favourably than the standard LPA offers to other LPs. The ILPA Principles discourage side letters that create hidden tiers of GP preference and encourage transparency regarding material GP-LP relationships. However, the ILPA Principles acknowledge that side letters are appropriate for co-investment rights (which are economic benefits within the control of the GP) and for governance rights (which allow specific LPs to participate in advisory committees or receive additional reporting).

The integration of side letters and co-invest rights documentation often creates interpretation challenges. If a side letter grants an LP "priority co-investment rights" and later an MFN provision comes into effect through a new LP subscription, the interaction between the priority rights and the MFN obligation may be ambiguous. Does the MFN provision override the priority rights, or do the priority rights retain their original character? Dispute resolution mechanisms in side letters (often arbitration) have been invoked to resolve these ambiguities, with mixed results. English courts have held that side letters should be interpreted in light of the main LPA's language and that ambiguities in MFN provisions will be construed against the party asserting the MFN right.

ILPA side letter principles also recommend that side letter copies be provided to the fund administrator and that material side letter terms be disclosed to the advisory committee (even if not to all LPs) to ensure that side letter obligations are tracked and fulfilled. Many disputes arise because side letters granting co-invest or reporting rights are not properly integrated into the fund's operational procedures, and the GP fails to offer promised co-investment opportunities or to provide promised reporting.

Legal Relationship Between Main Fund and Co-Invest Vehicles: Governance and Coordination

The Co-Investment Agreement

The legal relationship between the main fund and co-invest vehicles is typically defined through a combination of documents: the co-investment agreement (or side letter for individual investor co-invest rights), the SPV or parallel vehicle documentation, and potentially an advisory committee charter or governance memorandum.

The co-investment agreement typically addresses the following elements:

1. the types of investments subject to co-investment (portfolio company equity, debt, or secondary interests)
2. the mechanics of offering and participation (the GP shall offer co-invest opportunities to eligible investors on a specified basis, with investors having a specified window — often 5 to 10 business days — to decide on participation)
3. the capital call and distribution procedures (co-invest vehicles receive capital calls and distributions on a schedule aligned with the main fund, with specified timing gaps)
4. the pro-rata participation mechanics (if the main fund invests $50 million in a portfolio company and the co-invest vehicle invests $25 million, the co-invest vehicle holds 33 per cent of the portfolio company equity, pro rata)
5. the governance and decision-making process for portfolio company board representation, consent to material transactions, and voting at portfolio company shareholders' meetings

Conflicts Between Main Fund and Co-Invest Vehicles

A critical governance issue arises in connection with portfolio company decisions where the main fund and co-invest vehicles may have conflicting interests. For example, if a portfolio company has the opportunity to issue new preferred equity at a lower valuation than recent fundraising rounds, the main fund's directors (representing the main fund's interest as the majority equity holder) may favour the transaction to preserve the company's capital runway, while co-invest vehicle directors (representing minority shareholders) might object to the dilution. The co-investment agreement should specify that voting by the co-invest vehicle's directors is coordinated with the main fund's directors and that conflicts are resolved through the advisory committee or through a designated conflict resolution mechanism.

The interaction between the main fund's governance (its LPA, board of directors, advisory committee) and the co-invest vehicle's governance (its articles or ELP agreement, board or managers, and governance committee) requires careful drafting. Some funds provide that the co-invest vehicle is governed by substantially the same terms as the main fund (e.g., the same investment restrictions, valuation procedures, and reporting standards), while others allow the co-invest vehicle more flexibility (e.g., allowing direct co-invest vehicles to hold speculative or higher-risk securities not permitted in the main fund).

The use of "super-coordinator" or "transaction committee" governance mechanisms has become common in larger co-invest structures. A transaction committee (typically comprised of senior GP partners and one or two LP representatives) has authority to approve material portfolio company transactions, capital calls, and governance decisions affecting both main fund and co-invest vehicles. The committee's decisions are binding on both vehicles (subject to LPA restrictions on GP authority), which avoids the paralysis that can result from separate governance procedures for main fund and co-invest vehicle decisions.

Regulatory Treatment Under the Private Funds Act 2020

The Private Funds Act 2020 (PFA) establishes a comprehensive regulatory framework for private funds in the Cayman Islands, including requirements for fund registration, investor reporting, and ongoing compliance with CIMA (the Cayman Islands Monetary Authority). The regulatory treatment of co-invest vehicles under the PFA depends on whether the co-invest vehicle is itself classified as a "private fund" under the Act.

Classification and the Subsidiary Exemption

A "private fund" under the PFA is defined as a fund that pools investor capital and is not available to the public, subject to certain exceptions for family offices and small investment vehicles. A co-invest vehicle that accepts capital from multiple investors and pools that capital for investment in portfolio companies is potentially a private fund subject to registration and reporting requirements. However, the PFA provides an exemption for vehicles that are "subsidiaries" of a registered private fund and that invest solely in securities of the same issuer or in a limited set of issuers controlled by the parent fund.

Most co-invest vehicles in Cayman structures are structured to fall within this exemption. A parallel co-invest vehicle that invests in the same portfolio companies as the main fund (alongside the main fund) is a subsidiary of the main fund if the main fund holds a controlling interest in the co-invest vehicle or if the co-invest vehicle is wholly operated under the control of the main fund's GP.

The subsidiary exemption applies, and the co-invest vehicle itself is not required to register as a private fund.

Feeder Co-Invest Funds and Compliance Costs

However, if a co-invest vehicle is structured as a separate feeder fund with a distinct investor base and independent capital raising, it may be classified as a private fund in its own right, requiring separate registration and reporting to CIMA. Feeder co-invest funds that have $100 million or more in assets must file audited annual financial statements with CIMA and certifications regarding compliance with the PFA's operational and governance requirements. Smaller co-invest funds may use unaudited financial statements and streamlined reporting.

The Private Funds Act also requires that any entity classified as a private fund maintain records regarding its portfolio investments, valuation procedures, investor composition, and investment performance. These requirements apply to the co-invest vehicle if it is itself a private fund, which adds administrative and compliance costs. Many smaller PE managers therefore prefer to use SPV structures (where each portfolio company investment is housed in a separate vehicle) or to structure co-invest capital through LPs' direct participation in portfolio company SPVs, rather than through a dedicated parallel co-invest vehicle subject to PFA registration.

CIMA's regulatory guidance on co-invest vehicles emphasises that even if a co-invest vehicle is exempt from private fund registration (as a subsidiary), the co-invest vehicle remains subject to Cayman company law and must maintain statutory records. The GP remains responsible for ensuring that co-invest vehicles comply with Cayman law and regulatory requirements, even if CIMA does not directly supervise the vehicles.

Conflicts, Disputes, and Best Practices in Co-Invest Documentation

Co-investment structures create substantial conflict and dispute risk if documentation is ambiguous or if operational procedures fail to align with contractual commitments. Common dispute categories include the following.

First, disputes over co-invest capacity and allocation arise when the GP receives more co-invest interest from eligible investors than available deal capacity. If a deal has $50 million of available co-invest capital, and five LPs each request $20 million of participation, the GP must choose which LPs to accept. The co-investment agreement should specify the allocation mechanism: first-come-first-served, pro-rata allocation based on main fund commitments, or GP discretion (subject to MFN constraints). Ambiguity in allocation procedures creates disputes and damaged investor relationships.

Second, disputes over follow-on funding obligations are common. If an LP co-invests in a portfolio company's Series A funding round, is the LP obligated to participate in Series B, Series C, and subsequent rounds? If the LP declines to participate in a follow-on round, does its pro-rata interest in the company dilute? Should the LP's original investment be subjected to anti-dilution protection? These questions are negotiated in the side letter and co-invest agreement, but ambiguities frequently arise. ILPA principles recommend that follow-on participation be optional (not mandatory) for co-investors, allowing LPs to decide round-by-round whether to maintain their ownership stake or accept dilution.

Third, disputes over transaction fees arise from ambiguity in allocation. If a portfolio company pays a transaction fee or advisory fee to the main fund, should that fee be reduced proportionally to account for co-invest capital that the co-invest vehicle deployed? If the main fund charged $5 million in transaction fees for a $100 million deal and the co-invest vehicle contributed $30 million of that capital, should the co-invest vehicle receive a $1.5 million credit against its carried interest? Absent clear documentation, these disputes consume substantial management and legal time.

Fourth, disputes over governance and decision-making arise in connection with portfolio company transactions. The co-investment agreement must specify that co-invest vehicles' board representatives coordinate with main fund directors and do not pursue separate agendas that conflict with the main fund's strategic objectives. Where conflicts cannot be avoided (e.g., a co-invest vehicle disagrees with a proposed portfolio company capital raise), the agreement should provide for a conflict resolution mechanism, such as advisory committee arbitration or independent fairness opinion.

Best practices emerging from market experience include the following:

1. co-investment rights and mechanics should be clearly specified in side letters and co-investment agreements, with explicit treatment of capacity allocation, follow-on participation, and fee allocation
2. co-invest vehicles should be governed by substantially the same valuation, reporting, and compliance procedures as the main fund, to avoid divergence in treatment and associated disputes
3. transaction committees or coordinator governance mechanisms should be established to ensure aligned decision-making across main fund and co-invest vehicles
4. MFN provisions should be limited and should explicitly carve out specific investor classes or relationships to avoid cascading MFN cascades
5. operational procedures should be documented in an investment operations manual or fund governance memorandum, with explicit responsibility assignments for co-invest opportunity offering, capital call and distribution processing, and reporting to co-invest vehicle investors

Practical Integration: Co-Invest with Secondary Transactions and Continuation Vehicles

Secondary Market Transfers

Co-invest vehicles create particular complexity in the context of secondary market transactions (secondary share purchases from departing investors) and GP-led continuation vehicles that extend the fund's investment period.

In secondary transactions, the question arises whether sellers of main fund interests should be permitted to also transfer their co-invest vehicle interests. A departing LP selling its main fund interest may wish to retain its co-invest vehicle interests (because co-invest returns are often uncorrelated with main fund returns and represent direct exposure to specific portfolio companies). Alternatively, the departing LP might wish to exit all interests (main fund and co-invest) simultaneously. The documentation should specify whether co-invest vehicle interests are transferable in parallel with main fund interests or independently.

Continuation Vehicles

In continuation vehicles (vehicles that extend the fund's life by transferring performing or underperforming portfolio companies to a new fund), the treatment of co-invest vehicles requires careful coordination. If the main fund transfers a portfolio company to a continuation vehicle, and a co-invest vehicle held a minority stake in that portfolio company, the co-invest vehicle's interest must be addressed. Should the co-invest vehicle's interest be transferred to the continuation vehicle alongside the main fund's interest? Should the co-invest vehicle retain its original interest and continue to hold it independently? Should the co-invest vehicle's interest be subject to a tender offer (an opportunity for co-invest LPs to exit at a specified valuation)?

ILPA principles on continuation vehicles recommend that co-invest vehicle interests be treated consistently with main fund interests in the context of continuation transactions: if main fund LPs are offered a roll-over into the continuation vehicle, co-invest vehicle investors should receive a similar offer. Moreover, the valuation of the co-invest vehicle's interest in the transferred portfolio company should be transparent and should reflect the same valuation methodology used for the main fund's interest, adjusted only for the co-invest vehicle's specific terms (e.g., different capital structures or preferred return rights).

Conclusion and Practical Implications for Fund Operators

Co-investment has become standard in institutional PE and VC, driven by investor demand for fee efficiency and direct exposure to high-conviction deals. The structural frameworks used to accommodate co-investment in Cayman-domiciled funds — SPVs, parallel vehicles, and feeder structures — each present distinct advantages and operational trade-offs.

The contractual and documentary foundations of co-invest structures must address the mechanics of participation, fee and carry allocation, governance and conflict resolution, and the integration of co-invest vehicles with main fund reporting and compliance procedures. Ambiguities in these areas create substantial dispute risk and can damage investor relationships and fund operational efficiency.

MFN provisions in side letters, while protecting investor interests, can cascade and create unintended consequences if not carefully limited and documented. Best practices emphasise explicit carve-outs for specific investor classes and transparent disclosure of material GP-LP relationships affecting co-invest rights.

The regulatory treatment of co-invest vehicles under the Private Funds Act 2020 depends on whether the vehicles are classified as private funds themselves. Most structures avoid separate private fund registration by using subsidiary exemptions or SPV structures, but GPs must confirm the classification and ensure compliance with applicable requirements.

Fund operators should invest in clear operational procedures and governance mechanisms to track co-invest offerings, ensure aligned decision-making across main fund and co-invest vehicles, and prevent disputes over capital allocation and management fees. As co-investment becomes more complex and as investor bases become more diverse, the operational burden of managing multiple parallel investment vehicles increases, and the cost-benefit analysis of co-investment structures should be reassessed periodically.

If you are structuring co-investment vehicles for a Cayman-domiciled fund, navigating co-investment side letters, or resolving disputes over co-invest participation or fee allocation, Lexkara & Co provides comprehensive guidance on documentation, governance, and regulatory compliance. We work with fund sponsors to design co-invest structures that align investor interests, minimise operational complexity, and protect against the disputes that commonly arise in parallel vehicle environments.