Side Letter

A side letter is a supplementary legal agreement between a fund manager and a specific investor that modifies or supplements the terms of the main partnership or subscription agreement, granting customised rights, obligations, or disclosure provisions that differ from those afforded to other limited partners. In the family-office context, side letters typically address governance rights, reporting requirements, tax transparency, co-investment opportunities, fee arrangements, redemption terms, or regulatory compliance needs that are unique to the family's jurisdiction, reporting obligations, or investment policy constraints.

Family offices commonly negotiate side letters to secure enhanced transparency provisions, including access to underlying portfolio company financials, quarterly operational metrics, or detailed investment memoranda that exceed standard limited partner disclosures. Tax-related side letters may address withholding obligations, FATCA or CRS reporting requirements, treaty benefits, or jurisdiction-specific documentation needed for the family office's consolidated reporting. Governance provisions often include most-favoured-nation (MFN) clauses ensuring the family receives terms at least as favourable as those granted to subsequent investors, consent rights over key-person events or strategy drift, and participation rights in advisory committees. Fee-related side letters may establish reduced management fees, modified carried interest waterfalls, or preferential break-point structures for larger commitments, though regulatory scrutiny has increased around discriminatory fee arrangements, particularly under SEC examination priorities and ESMA guidelines.

The enforceability and regulatory treatment of side letters varies significantly across jurisdictions, with US SEC-registered advisers subject to disclosure obligations under Form ADV and fiduciary duty constraints that limit preferential treatment, while offshore funds domiciled in the Cayman Islands or Luxembourg operate under different disclosure regimes. AIFMD provisions in the European Union impose specific transparency requirements regarding preferential treatment granted through side letters, requiring disclosure to other investors in certain circumstances. Family offices should maintain comprehensive side letter registers, ensure provisions do not create material economic disadvantages to other investors that could trigger legal challenges, and structure MFN clauses carefully to avoid unintended consequences when subsequent investors negotiate different terms. Tax authorities increasingly scrutinise side letter arrangements for substance-over-form considerations, particularly where fee rebates or preferential allocations could be recharacterised as taxable distributions or deemed transactions.