Buying a Partial or Majority Stake in a Business: Agreements, Price, and Control

Not every acquisition is a 100% purchase. A buyer may want to acquire a minority stake in a business alongside the existing owner. A buyer may want to acquire a controlling majority, 51% or more, while the seller stays on and keeps a piece of the upside. Or a buyer and seller may agree on a staged structure: a majority stake now, with the remaining interest transferring later on defined terms. Each of these is a real, common deal structure, and each needs its own purchase agreement and governance framework, not a modified version of a full-acquisition template.

This guide covers how a partial buy-in differs from buying a whole company, the documents involved, how minority and majority stakes get priced, staged purchase structures, governance protections for the buyer, seller rollover, SBA financing rules for partial ownership changes, and how due diligence and tax treatment shift when the seller remains an owner after closing.

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How a Partial Buy-In Differs From a Full Acquisition or a Partner Buyout

In a full acquisition, the seller exits entirely and the buyer takes on 100% of the business, its risk, and its future decisions. A partial buy-in is different because the seller keeps a stake, keeps a voice in governance to some degree, and keeps an economic interest in how the business performs after closing. That changes the incentive structure. A seller who is walking away entirely wants the highest price today. A seller who is keeping 40% or 49% has a real interest in the business succeeding under the new ownership, which can align the parties around a fair price rather than an adversarial one, but it also means the buyer inherits a co-owner, not a clean slate.

A partial buy-in is also distinct from a partnership buyout, even though the documents overlap. A partnership buyout is one existing partner buying out another existing partner's interest, someone who already has skin in the business, knows its history, and is negotiating from inside the ownership structure. A partial buy-in typically involves an outside buyer purchasing into a business for the first time, either alongside a continuing owner or by acquiring majority control while the seller rolls part of their equity forward. If you already hold an interest in the business and are looking to buy out a co-owner, our partnership buyout guide covers that transaction specifically. This guide is for buyers coming in from outside who are acquiring less than 100%.

Structuring a minority or majority stake purchase? Alex Lubyansky drafts the purchase agreement and the governance terms together, not as an afterthought. Request a consultation →

The Documents a Partial Buy-In Requires

A partial buy-in generally requires more paperwork than a full acquisition, not less, because two things have to be documented instead of one: the transfer of equity, and the ongoing relationship between the buyer and the remaining owner.

Document	Purpose
Stock or membership interest purchase agreement	Governs the sale itself: purchase price, representations and warranties about the business and the equity being sold, indemnification, and closing conditions. This is the document that actually transfers ownership of the stated percentage.
Amended operating agreement or shareholders agreement	Governs how the buyer and the continuing owner will run the business together after closing: voting rights, board or manager composition, distribution policy, and decisions that require more than a simple majority vote.
Buy-sell provisions	Defines what happens if either owner later wants to sell, dies, becomes disabled, or the owners reach a deadlock. Frequently added or substantially rewritten as part of the buy-in itself, since a business with a single owner rarely has a functioning buy-sell mechanism already in place.

Skipping the second and third document sets is the most common mistake in partial buy-in transactions. A buyer who closes on the purchase agreement alone, without an updated operating agreement or shareholders agreement, has bought equity into a governance structure that may still be written for a single owner. That gap surfaces the first time the buyer and the continuing owner disagree on a material decision.

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Pricing a Minority vs. a Majority Stake: Why Control Matters More Than Percentage

Percentage ownership and control are not the same thing, and pricing follows control, not percentage alone. A minority stake, one that does not carry the ability to direct major business decisions, is typically priced at a discount to its pro-rata share of the business's full value. The buyer is not acquiring the ability to sell the company, set its direction, or control distributions, so the interest is worth less per percentage point than a controlling stake.

A majority stake, 51% or more, trades closer to full pro-rata value and can carry a control premium, since the buyer can direct the business going forward, including major decisions the minority owner cannot block absent specific reserved-matter protections. But the size of the stake by itself does not guarantee meaningful control. A 51% owner without board control provisions, without the ability to remove management, or bound by supermajority voting requirements written into the operating agreement can hold less practical authority than the number suggests. Before agreeing to a price, both sides need to agree on exactly what rights come with the percentage, since that, not the percentage alone, is what is actually being priced.

Staged Purchases: 51% Now, the Balance Later

A common structure has the buyer acquiring a majority stake, often 51%, at closing, with an agreement to purchase the remaining interest at a later date. This lets the buyer take operational control while the seller retains a stake through the transition period, and it can bridge a valuation gap or a financing gap that would otherwise stall the deal. Getting this structure right requires several elements to be defined in writing at the outset, not negotiated later when the parties may have less goodwill:

Option vs. Obligation

A call option gives the buyer the right, but not the obligation, to purchase the remaining stake. A put option gives the seller the right to require the buyer to purchase it. Many staged deals use both, a put/call structure, so either party can trigger the second closing under defined circumstances. Decide upfront whether the second-stage purchase is a right either party can invoke or a firm obligation on a fixed date.

Price Formula

Fixing a dollar price for a purchase that may not close for a year or more rarely works well, since the business's value can move in either direction. Most staged deals use a formula instead, tied to a trailing EBITDA multiple, a valuation methodology agreed in advance, or a third-party appraisal process, so the eventual price reflects the business's actual performance rather than a number set before anyone knows how the transition period will go.

Triggers

Common triggers include a fixed calendar date, the passage of a defined holding period, or a specific event such as the buyer securing financing for the second tranche. Vague triggers, such as "when the business is stable," invite disputes. Define the trigger as an objective, calendar-based or metric-based event.

Financing for the Second Tranche

If the buyer expects to finance the second-stage purchase, whether through a lender, seller financing, or business cash flow, that plan should be addressed at the outset, including what happens if financing is unavailable when the trigger date arrives. A staged agreement without a financing contingency can leave the buyer contractually obligated to close a purchase it cannot fund.

Considering a staged purchase, majority now with the balance later? Get the option, price formula, and triggers documented before you sign anything. Request a consultation →

Governance Protections for the Buyer

Whether the buyer holds a minority stake or a majority stake, governance provisions negotiated at the time of the buy-in determine how much practical authority actually comes with the equity. These protections need to be written into the amended operating agreement or shareholders agreement, not assumed from the percentage owned.

Board or manager seats. A buyer acquiring a meaningful stake, particularly a majority, typically negotiates board or manager representation proportional to or exceeding the ownership percentage, so decision-making authority tracks the investment.
Reserved matters. A defined list of major decisions, new debt, a sale of the company, additional equity issuances, changes to the business's core operations, that require consent from both owners regardless of who holds voting control. These protect a minority owner from being overridden on the decisions that matter most, and can protect a majority owner from a minority veto on routine matters if scoped narrowly.
Information and inspection rights. The right to receive regular financial statements and to inspect the company's books and records, so an owner without day-to-day operational control still has visibility into how the business is performing.
Drag-along and tag-along rights. Drag-along rights let a majority owner force a minority owner to join a sale of the company on the same terms, so a minority stake cannot block an exit. Tag-along rights let a minority owner sell alongside the majority owner on the same terms, so the majority owner cannot exit on favorable terms while leaving the minority owner behind.
Deadlock provisions. A defined process for resolving a dispute where the owners cannot agree, ranging from mediation to a buy-sell trigger to a forced sale process, so a disagreement does not paralyze the business indefinitely.

Seller Rollover: When the Seller Keeps a Stake

In many partial buy-ins, particularly majority purchases, the seller does not simply retain an existing minority interest; the seller rolls part of the sale proceeds forward into equity in the post-closing entity. This aligns the seller's interest with the business's future performance and can bridge a valuation disagreement, since the seller effectively bets on the business's continued success under new ownership rather than taking the full price in cash today. For a detailed look at how rollover structures work, including tax deferral mechanics and typical rollover percentages, see our rollover equity guide.

A seller who rolls equity forward should be treated, for governance purposes, the same as any other minority owner, with the same information rights, reserved-matter protections, and exit mechanics negotiated up front. The fact that the seller previously ran the business does not automatically entitle them to more governance authority than their post-closing ownership percentage would otherwise carry, and the new operating agreement should say so explicitly.

SBA 7(a) Financing for Partial Changes of Ownership

SBA 7(a) financing can be used for certain partial changes of business ownership, not only for full acquisitions. The SBA's Standard Operating Procedures set specific conditions on when a partial-ownership transaction is eligible, including requirements around the resulting ownership and control structure after the transaction closes. These rules have been updated in recent years and continue to be refined, so treat any general description of eligibility as a starting point, not a substitute for confirming the current SOP requirements, and your specific transaction's eligibility, with your SBA lender before you build a deal structure around this financing path.

For buyers structuring a majority stake purchase with SBA financing, involving SBA acquisition counsel early matters even more than in a full-acquisition SBA deal, since the lender will need to underwrite not just the purchase price but the post-closing ownership and control structure, including any rollover equity the seller retains.

Due Diligence and Tax Considerations When the Seller Stays

Due diligence in a partial buy-in still covers the same ground as a full acquisition, financials, contracts, liabilities, licenses, and operational risk, but it also needs to examine the specific terms the buyer will be bound by as a co-owner going forward: existing debt covenants, related-party arrangements the continuing owner may have with the business, and any prior distributions or compensation practices that will need to change or continue under the new ownership structure. A finding during diligence can also change more than price. Our guide on price renegotiation after due diligence covers how findings get addressed through mechanisms beyond a straight price cut, several of which, escrow increases and indemnification changes in particular, apply directly to partial buy-in transactions.

Tax treatment in a partial buy-in depends heavily on entity type, whether the transaction is structured as a stock, membership interest, or asset purchase, and whether any portion of the seller's proceeds is rolled forward as equity rather than taken in cash. These questions are genuinely case-specific, and this guide does not offer tax advice. Counsel and your CPA should coordinate on entity structure and tax treatment before the purchase agreement is finalized, not after closing.

Frequently Asked Questions

Can I buy 51% of a business?

Yes. Buying 51% of a business is a majority stake purchase. You acquire control of the entity through a stock or membership interest purchase agreement, and the seller retains the remaining 49%. Because the seller stays on as a minority owner, the deal needs an amended operating agreement or shareholders agreement that spells out how decisions get made, how the seller's remaining stake gets valued if either side wants to exit later, and what happens if the two owners disagree. Financing, due diligence, and governance all look different from a 100% purchase because the seller has an ongoing stake in outcomes.

What is a partial buy-in agreement?

A partial buy-in agreement is the purchase agreement and related governance documents used when a buyer acquires less than 100% of a business, whether a minority stake or a controlling majority. It typically includes a stock purchase agreement or membership interest purchase agreement covering the price and closing mechanics, plus an amended operating agreement or shareholders agreement covering how the buyer and the remaining owner will govern the business together. Buy-sell provisions, often added or updated as part of the same transaction, define what happens if either owner later wants to sell, dies, becomes disabled, or triggers a deadlock.

How is a minority stake priced?

A minority stake is generally priced at a discount to its pro-rata share of the business's full enterprise value, reflecting the buyer's lack of control over major decisions, limited ability to force a sale or distribution, and reduced marketability compared to a controlling interest. The size of that discount is negotiated, not fixed, and depends on what governance rights the buyer secures alongside the equity, such as board representation, information rights, or veto rights over specific major decisions. A majority stake trades closer to its full pro-rata value, and can carry a control premium, because the buyer can direct the business going forward.

What protects a minority owner?

A minority owner's protection comes from the governance provisions negotiated into the operating agreement or shareholders agreement at the time of the buy-in, not from the size of the stake itself. Common protections include reserved matters requiring minority consent for major decisions such as new debt, a sale of the company, or issuing additional equity; information and inspection rights; tag-along rights that let the minority owner sell alongside the majority owner on the same terms; and a defined valuation mechanism and buyout process if the relationship breaks down. Without these provisions in writing, a minority owner has limited practical leverage regardless of the percentage held.

Can an SBA loan fund a partial buyout?

SBA 7(a) financing can be used for certain partial changes of ownership, subject to conditions under the SBA's Standard Operating Procedures, including rules on the resulting ownership structure and the buyer's post-transaction control. These requirements are detailed and have been revised in recent years, so confirm the current SOP requirements and your specific transaction's eligibility with your SBA lender before relying on this financing path for a partial or staged purchase.

Structuring a Purchase That Is Not a Full Acquisition

A minority stake, a majority stake, or a staged buy-in each needs its own purchase agreement and governance terms. Review the related guides before you structure the deal.

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