What Is a Side Letter?

Private equity investing often comes with more customization than traditional public market investing. For high-net-worth individuals, family offices, and institutional investors, that flexibility can create opportunities to negotiate specific terms that can better align with investment goals, tax considerations, liquidity needs, or reporting expectations. One of the most common tools used to formalize these negotiated terms is the side letter.

What is a side letter? A side letter is a separate agreement between an investor and a private investment fund that modifies, clarifies, or supplements the terms of the main fund documents. While side letters are common in private equity, venture capital, hedge funds, and private credit, they can also introduce legal, operational, and governance complexities that investors exploring private markets should understand before signing.

In this article, the multi-disciplinary financial team from Avidian Wealth Solutions will lay out how side letters can work (and when they may or may not make sense) as an important part of evaluating an opportunity strategically.

What is a side letter in private equity?

A side letter is a private contractual agreement between an investor and a fund manager, also called a general partner (GP). It exists alongside the fund’s governing documents, such as the limited partnership agreement (LPA), subscription documents, and offering memorandum.

The purpose of a side letter is usually to grant one investor terms or accommodations that differ from the standard terms offered to all investors in the fund.

These agreements are especially common in closed-ended funds, which are investment vehicles that raise capital for a fixed period of time and typically have a defined lifespan of 7–12 years. Private equity funds are usually structured this way because investments are intended to be held long-term before eventually being sold or exited.

Side letters may address issues such as:

• Reduced management fees
• Enhanced reporting rights
• Tax accommodations
• Co-investment opportunities
• Environmental, social, and governance (ESG) restrictions
• Confidentiality obligations
• Regulatory compliance matters

In many cases, larger investors have more leverage to negotiate side letters because they are committing significant capital to the fund.

Why do investors request side letters?

Not all investors enter a private equity fund with the same priorities or constraints. A pension fund may face different reporting obligations than a family office. An international investor may need specific tax language. A wealthy entrepreneur may want more visibility into portfolio company activity.

Side letters allow these investors to tailor certain aspects of the relationship without rewriting the entire fund agreement for every participant. Some common motivations include:

• Fee and expense adjustments: Large investors may negotiate reduced management fees or preferred economics. This is particularly common when an investor commits substantial capital early in the fundraising process.
• Regulatory and compliance needs: Institutional investors often require language addressing regulations, fiduciary obligations, or internal governance standards.
• Tax treatment: Certain investors may request provisions designed to help minimize tax inefficiencies or address jurisdiction-specific concerns.
• Enhanced transparency: Some investors want more detailed reporting, portfolio updates, or valuation information than the standard investor package includes.
• Strategic access: Investors may seek access to co-investment rights (more on this later), which allow them to invest directly in individual deals alongside the fund.

Common side letter provisions

Although side letters can vary significantly, several provisions appear frequently across private market investments, including:

Most favored nation (MFN) rights

Most favored nation rights allow an investor to adopt certain more favorable terms granted to other investors through separate side letters.

For example, if another investor negotiates improved reporting access or lower fees, an MFN clause may allow eligible investors to elect similar benefits.

MFN provisions are often subject to limitations, including minimum investment thresholds or exclusions for regulatory-specific accommodations.

Co-investment rights

Co-investment rights give investors the opportunity to participate directly in deals alongside the fund itself. These arrangements can appeal to investors seeking:

• Greater portfolio concentration
• Reduced fee exposure
• Increased control over capital deployment
• Access to specific industries or transactions

However, co-investment opportunities are not always guaranteed and may depend on deal size, availability, or the GP’s discretion.

Reporting and transparency requirements

Some investors request customized reporting schedules, enhanced financial disclosures, or access to portfolio company data.

Institutional investors, in particular, may require detailed information to satisfy internal oversight obligations.

Excuse and exclusion rights

These clauses allow an investor to opt out of participating in certain investments that may conflict with legal, ethical, or policy restrictions. For instance, an investor may request exclusion from investments involving:

• Tobacco
• Firearms
• Sanctioned jurisdictions
• Certain environmental exposures

Tax and structuring accommodations

Cross-border investors frequently negotiate tax-related provisions to address withholding taxes, unrelated business taxable income (UBTI), or jurisdiction-specific concerns.

Common scenarios where side letters may arise

Side letters are often associated with large institutional investors, but they also appear in high-net-worth and family office investing situations:

Investor Type	Description
Early anchor investors	An investor committing capital early in the fundraising cycle may negotiate more favorable economics in exchange for helping the fund gain momentum.
Family office investors	Family offices may request customized reporting or investment restrictions aligned with family governance priorities.
International investors	Non-U.S. investors frequently require tax-related accommodations or jurisdiction-specific language.
Strategic industry investors	An investor with industry expertise may negotiate information-sharing rights or co-investment access in sectors where they have operational knowledge.

Legal and regulatory considerations

Although side letters can create flexibility, they also introduce legal and compliance considerations for both investors and fund managers.

One major concern is fairness among investors. If side letter provisions materially disadvantage other investors, disputes may arise regarding fiduciary duties or disclosure obligations.

Fund managers must also consider whether certain arrangements create operational burdens or conflicts with the fund’s governing documents.

Regulators have increasingly scrutinized private fund practices involving preferential treatment and disclosure transparency. In recent years, private fund regulation has focused more heavily on whether investors are being treated consistently and whether material side letter terms are adequately disclosed.

Investors should carefully review whether:

• The side letter conflicts with the limited partnership agreement
• The GP has authority to grant the requested rights
• Disclosure obligations apply to certain provisions
• Operational systems can realistically support the arrangement

Because side letters are negotiated documents, vague or poorly drafted language can create future disputes.

Operational challenges of side letters

From an operational standpoint, side letters can become difficult to manage as funds grow more complex. A fund with dozens of customized agreements may face challenges related to:

• Tracking individualized obligations
• Maintaining consistent investor communications
• Managing reporting timelines
• Monitoring compliance requirements
• Administering different fee structures

For investors, this matters because operational complexity can increase the likelihood of errors, delays, or misunderstandings.

It is also important to recognize that not every requested provision is practical. A GP may reject certain requests if they create excessive administrative burdens or perceived inequities among investors.

In some cases, investors may focus too heavily on negotiating favorable side letter terms while overlooking broader considerations about the underlying investment itself, including manager quality, strategy alignment, liquidity risk, and portfolio diversification.

Questions to ask before requesting a side letter

Before requesting a side letter, investors should evaluate the broader purpose behind the request. Some helpful questions include:

• What problem is the side letter trying to solve?
• Is the requested accommodation commercially reasonable?
• Could the provision create operational friction?
• Does the GP have a history of granting similar requests?
• Will the provision materially improve the investment experience?
• Are there unintended legal or tax consequences?

Investors should also assess whether negotiating aggressively over ancillary terms could affect their long-term relationship with the fund manager.

Remember: private markets are relationship-driven environments, and reputation often matters as much as economics.

Call Avidian for a holistic approach to private equity opportunities

Side letters are an important feature of the private equity landscape because they allow investors and fund managers to address specialized needs that may not fit neatly into standard fund documents. At the same time, these agreements can introduce additional complexity, particularly when they involve customized economics, reporting obligations, regulatory accommodations, or co-investment arrangements.

But while side letters may offer flexibility and strategic benefits in certain situations, what is a side letter good for if it’s not integrated into a much larger private market investment framework?

This is where Avidian Wealth Solutions may be able to help investors approach private market opportunities more holistically. Rather than focusing narrowly on a single document or negotiated term, our team works with investors to determine how a private equity investment fits within the context of their overall wealth plan, risk exposure, cash flow needs, estate planning objectives, and long-term goals.

If you are a high-net-worth investor entering private markets, schedule a conversation or visit us in Houston, Austin, Sugar Land, or The Woodlands to learn how side letters function — and how they may interact with your broader investment strategy.

Important Disclosure

This article is provided for informational and educational purposes only and should not be construed as investment, legal, tax, accounting, or other professional advice. The information contained herein is general in nature and may not be applicable to your individual circumstances. Investors should consult their own legal, tax, and financial professionals before making any investment decisions. Investing involves risk, including the possible loss of principal. Private equity and other alternative investments are speculative, illiquid, involve a high degree of risk, and are not suitable for all investors. Past performance is not indicative of future results.

More Helpful Articles by Avidian: 

• A Guide to Estate Planning for Cognitive Decline
• Why Life Insurance Is a Crucial Part of Financial Planning
• The Avidian Estate Planning Glossary: Roles, Responsibilities, & Key Terms
• Joint Trust vs. Individual Trust: Which is Right for You?
• 7 Considerations When Managing Digital Assets

---

Please read important disclosures here