How to manage a sidecar investment vehicle

What is a sidecar investment vehicle?

A sidecar investment vehicle is a specialized fund structure that allows a fund’s existing investors to participate in a specific investment deal alongside the main fund. This structure is typically a special purpose vehicle (SPV) that is managed by the fund's general partner (GP). The GP uses the sidecar to pool capital from their limited partners (LP) for a single, targeted investment.

Think of it like a motorcycle with a sidecar attached. The GP is the driver, navigating the investment landscape based on the expertise required to manage a private equity (PE) fund successfully. The LPs in the main fund are passengers on the motorcycle, and the sidecar offers a select group of those LPs a chance to ride alongside the GP for a specific, targeted journey—a single investment opportunity.

The GP first identifies a compelling deal—often formalizing the valuation, due diligence, and rationale in an investment memo—and then creates the sidecar to gather the necessary capital to fund it. This allows the GP to make a larger investment in the target company than they could with the main fund alone. At the same time, it gives interested LPs more exposure to a deal that the GP has high conviction in.

How sidecars differ from funds and SPVs

While a sidecar is a type of SPV, its purpose and investor base make it distinct. To fully grasp the concept, it's helpful to see how a sidecar compares to other common investment structures. The key distinction is the sidecar's direct relationship with a main fund and its existing LPs.

A main fund is designed to invest in a portfolio of multiple companies, spreading risk across different assets within their investment portfolios according to a broad investment thesis developed during portfolio construction. In contrast, a standard SPV is a standalone vehicle that can be used by any group of accredited investors, like an angel syndicate, to invest in a single company, and it doesn't require a preexisting main fund.

A sidecar vehicle sits between these two. It is also a single-asset vehicle, but sidecar investors are primarily the existing LPs from the GP's main fund, creating a focused opportunity for a group that already has a relationship with the fund manager.

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Why GPs use sidecar vehicles

GPs use sidecar vehicles for several strategic purposes, such as exceeding fund concentration limits or making off-thesis investments. One of the most common drivers is the need to execute follow-on investments to support existing portfolio companies.

As the venture capital market has shifted, the need for this kind of bridge financing has become more frequent, partly because the average holding period for portfolio companies has increased, requiring more capital over a longer duration. Bridge rounds have become a major feature of the early‑stage market: Across 2023, 36% of all priced seed financings on Carta were bridge rounds, and that share rose to about 40% in 2024. In Q3 2023 specifically, bridge rounds became unusually common at multiple stages while the use of investor‑friendly terms like >1x liquidation preferences, cumulative dividends, and participation dropped to multi‑year lows.

GPs typically use sidecar vehicles in a few common scenarios:

• To exceed concentration limits: The governing fund documents, like the limited partnership agreement, often include rules that restrict how much capital can be put into a single company. These concentration limits exist to ensure the fund remains diversified and avoids over-concentrating its risk in a single asset. A sidecar allows the GP to invest more in a high-conviction deal than the main fund’s rules permit, without breaking the fund's diversification rules.

• To make off-thesis investments: Sometimes a GP finds a compelling sidecar opportunity, like an early-stage company, that falls outside of the fund’s investment thesis. A sidecar provides the flexibility to pursue the deal without violating the fund's mandate, which is important for maintaining trust with LPs who invested based on that specific strategy.

• To execute follow-on investments: When a fund is near the end of its life or has deployed most of its capital, it may lack the reserves, or dry powder, for these follow-on rounds. A sidecar allows LPs who are excited about a company's progress to double down on a winner and provide the needed startup funding for its next stage of growth, with some vehicles deployed specifically for additional follow-on investments.

Common sidecar structures: Overage, annex, and top-up funds

Sidecars can be structured in several ways depending on their specific purpose. Understanding these variations can provide deeper insight into a GP's strategy and how they manage their portfolio and capital.

Here are a few common types of sidecar funds:

• Overage funds: These are used to invest the amount of a deal that is "over" the main fund's concentration limit. This structure is the direct solution for when a GP wants to take a larger-than-planned stake in a company they believe has exceptional potential.

• Annex funds: These are raised after the main fund's official investment period has ended. Their specific purpose is to provide follow-on capital to existing portfolio companies that need more funding to reach liquidity or an exit, acting as an "annex" to the original fund's strategy.

• Top-up funds: These are raised during the main fund's investment period to take advantage of new market opportunities. They invest alongside the main fund in new deals, effectively "topping up" the firm's investment capacity when a great deal requires more capital than the main fund can provide on its own.

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How to manage the sidecar vehicle lifecycle

The administrative process for managing an SPV has historically been complex and manual, creating a significant administrative burden for fund managers. This complexity is amplified by the wide variation in how SPVs are structured; according to a 2024 analysis, the number of LPs in an SPV between $20 million and $30 million can range from just three to as many as 44. Managing communications, capital calls, and distributions for dozens of LPs in a single-deal vehicle highlights the inefficiency that modern platforms are built to solve.

Modern technology has transformed these workflows, making it manageable even for lean teams. The lifecycle of a sidecar can be broken down into three main stages, from initial setup to ongoing administration. Each stage presents its own set of challenges and operational requirements that you need to be prepared for.

Step 1: Forming the legal entity

The first step in the SPV formation process for a sidecar is creating a new legal entity. This is typically a Delaware LLC or limited partnership, chosen for their favorable business laws and extensive legal precedent. This process involves drafting operating agreements, managing state filings, and obtaining a federal tax ID number.

This is where a dedicated platform can simplify the process. Carta’s SPV Formation and Administration helps manage this administrative legwork by working with your fund’s legal counsel to handle entity setup, provide standard legal document templates, and manage regulatory filings. This frees you to focus on the investment itself and your relationship with your LPs.

Step 2: Onboarding investors and closing capital

Once the entity is formed, the next operational challenge is bringing LPs into the sidecar and collecting their capital commitments through a capital call. Traditionally, this involved mailing physical subscription documents, which finalize the deal points often outlined in term sheets, chasing down signatures, and manually tracking progress in spreadsheets, all while managing sensitive investor information over insecure email threads. This process was not only inefficient but also created risk and a poor experience for sidecar investors.

For J.B. Handley, co-founder of PE firm Bochi Investments, the simplicity of a platform-based approach was a transformative shift. "When I ran my first SPV through Carta, I almost couldn’t believe how easy it was," Handley says. This ease of use extends to investors, making them more comfortable with the process. "Knowing how easy Carta is has actually allowed me to drop my minimums and include more people in my deals."

A modern solution like Carta provides a professional, secure, and efficient closing experience. LPs use a dedicated LP Portal to review and sign subscription documents digitally. Integrated services for know your customer (KYC) and anti-money laundering (AML) help you vet investors by confirming their identity and screening them against regulatory watchlists to ensure compliance from day one, making the entire process seamless for both the GP and the LPs.

Step 3: Administering the investment and reporting to LPs

After the investment is made, the ongoing management responsibilities begin. These include tracking the investment fund performance, preparing quarterly financial reports, issuing Schedule K-1s for taxes, and managing communications with LPs. If managed manually, these tasks can become a significant time commitment and a source of potential errors.

Carta's Fund Administration serves as the single source of truth for the sidecar. The platform automates fund accounting, provides LPs with real-time performance metrics like multiple on invested capital (MOIC) in their portal, and streamlines year-end tax and audit processes. This level of automation and integration is what allows firms to scale their strategies effectively. As Hemanth Gollar, founder of High Circle Ventures, explains, this efficiency was critical to his firm's expansion. "High Circle Ventures could not have grown exponentially in just six or seven months if it hadn’t been for the Carta platform," he said.

How are sidecar economics structured?

Sidecar investments typically offer more favorable terms, as it's common for GPs to reduce or even waive management fees and carried interest. The economic terms of a sidecar are a key reason why LPs find them attractive. Understanding these structures is essential for both GPs and LPs to evaluate an opportunity, as they often differ significantly from the terms of a main fund.

Data on special purpose vehicles shows that waiving fees is the majority practice. According to a 2024 Carta report analyzing 2,442 SPVs, only 44% charge any management fees at all. For many fund managers, this is a common approach to remove a potential obstacle for LPs, especially on follow-on deals where LPs may already be paying fees on other funds.

• Management fees are what LPs pay the GP to cover the fund's operational costs

• Carried interest is the GP's share of the profits from an investment, which serves as their primary performance incentive

Recent data on SPVs shows that nearly 90% of SPVs use the vehicle’s committed capital as the baseline for calculating management fees. Unlike traditional “blind pool” funds, where LPs often pay fees on uncalled capital, SPVs offer a more efficient cost structure. Since 100% of an SPV’s committed capital is typically deployed into the deal immediately, LPs avoid “fee drag”(paying management fees on capital that isn't yet earning a return) on idle capital.

By offering a “no fee, no carry” sidecar—which bypasses complexities like a hurdle rate—GPs can provide a compelling opportunity for LPs to increase their exposure to a specific deal without additional costs. The negotiation of these terms reflects the alignment between the GP and LPs.

How to manage conflicts and compliance

For any fund CFO, GP, or those making investment decisions, upholding your fiduciary duty and managing risk are paramount. A fiduciary duty is the legal obligation to act in the best interest of your investors. Because there are inherent conflicts of interest with sidecar arrangements, the primary one to manage is ensuring fairness between the LPs of the main fund and the LPs participating in the sidecar.

The “cherry-picking” risk and regulatory exemptions

A major area of concern is the risk of "cherry-picking," where a GP might be tempted to allocate the most promising high-return deals to a sidecar (which might have different economics or favored investors) rather than the main fund.

To prevent this type of unfairness, the Investment Company Act of 1940 generally prohibits affiliated funds—such as a main fund and a sidecar managed by the same GP—from engaging in joint transactions, which includes investing in the same portfolio company at the same time.

Utilizing 3(c)(1) or 3(c)(7) exemptions helps funds navigate the Investment Company Act. However, GPs should still maintain robust allocation policies to address fiduciary obligations regarding potential cherry-picking or preferential treatment.

Best practices for fairness

To mitigate these potential conflicts, you should adhere to a set of best practices that promote transparency and fairness.

• Offer opportunities on a pro-rata basis: This means if an LP has a certain percentage stake in the main fund, they get the option to take the same percentage stake in the sidecar, a best practice for ensuring fairness as opportunities are typically offered to existing LPs on a pro rata basis before being shown to third-party co-investors.

• Maintain clear allocation policies: These are the "rules of the road" for deciding which deals go into which vehicle. Having these policies in writing prevents accusations of cherry-picking the best deals for a select few, a common concern in deal-by-deal investing.

• Disclose all terms transparently: Clear communication about all fees and economic structures is the best defense against misunderstandings. Ensure all parties involved know exactly what they are agreeing to.

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Integrating sidecars into your fund strategy

Sidecars are more than just one-off fixes for portfolio constraints; they are a strategic component of a modern fund manager's approach to agile capital deployment and enhanced LP relations. When managed effectively, they can become a core part of your firm's investment strategy.

By using sidecars, you can seize unique opportunities, express high conviction in your best ideas, and offer your LPs more ways to engage with your firm's deal flow. Sidecars can be a powerful tool for strengthening LP relationships. By creating bespoke pools of capital for co-investments, GPs can offer their most engaged LPs a way to gain more visibility and autonomy than is typical in a traditional fund structure, deepening the partnership. The ability to execute these vehicles without getting bogged down in administrative tasks is what allows you to realize their true strategic value.

As Gollar puts it, "Either you innovate or you’re extinct." For many fund managers, integrating sidecars and other SPVs is a key innovation to facilitate bespoke investments. Data shows this is a significant long-term trend: The annual count of new SPV formations on Carta has increased by 116% over the past five years. By leveraging an integrated platform like Carta, you can execute a sophisticated sidecar investing strategy that strengthens LP relationships and enhances returns, all without the administrative drag of manual processes.

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Frequently asked questions about sidecar investments

What is the difference between a sidecar and co-investment?

A sidecar is a specific type of co-investment vehicle structured and managed by the GP for the fund's LPs. The term co-investment is broader and can also refer to an LP investing directly in a company alongside the fund, separate from any vehicle the GP has created.

What are the tax implications of a sidecar investment?

When structured as a pass-through entity like an LLC or LP, a model also used by the typical search fund, the sidecar itself is not taxed. Instead, investors receive a Schedule K-1 and are responsible for reporting their share of any income or gains on their personal tax returns.

Can a sidecar vehicle invest in more than one company?

While most sidecars are created for a single deal, some structures like overage or top-up funds can be blind-pool vehicles. These are designed to invest in multiple opportunities that meet certain predefined criteria.