How to Partner With Another Business: Structure, Terms, and Taxes

To partner with another business, you and the other side pick a legal structure, sign a written agreement that spells out money and control, register the new entity with your state, and get an Employer Identification Number from the IRS. Filing fees to register are typically under $300, though the figure varies by state and entity type.¹ The order matters: the structure you choose shapes what goes in the agreement, what you file, and how you’re taxed.

Pick a Legal Structure

The structure decides who controls the business, who is personally on the hook for its debts, and how the IRS treats its income. Most partnership-style entities are governed by some version of the Uniform Partnership Act, adopted in various forms across the states.² Five options are common when two businesses join up:

A general partnership forms automatically the moment two or more people start doing business together. No state filing. The tradeoff is unlimited personal liability: creditors can pursue any partner’s personal bank accounts, home, or other assets for the full amount of a business debt.
A limited partnership (LP) has at least one general partner who runs things and carries full personal liability, plus limited partners who invest but stay out of daily management and risk only what they put in.
A limited liability partnership (LLP), common among accountants and lawyers, shields each partner from the partnership’s debts and from malpractice by other partners. A partner remains liable for malpractice they personally commit.
A limited liability company (LLC) blends partnership-style flexibility with corporate-style liability protection. Its owners are members, not partners, and it runs on an operating agreement rather than a partnership agreement.
A joint venture is a temporary collaboration between two businesses on a single project, often housed inside an LLC or partnership that exists only for that project.

If liability protection matters to you, the general partnership is the riskiest choice. An LP, LLP, or LLC limits your personal exposure at the cost of state registration and ongoing filings.

Settle the Terms Before You Draft

A strong agreement prevents the disputes that break partnerships apart: who put in what, who gets how much, and who can make which decisions. Work these points out with your partner in plain language before anyone writes legal prose.

Full legal names and business addresses of every founding partner or member.
Capital contributions. The exact cash, property, or services each side is putting in. These figures set each partner’s starting ownership stake.
Profit and loss allocation. The percentages each partner receives from profits and bears in losses. Splits don’t have to match ownership percentages, but they must be stated clearly.
Management authority. Who can sign contracts, hire employees, and approve spending, and which decisions require unanimous consent.
Admissions and departures. How new partners come in, and what happens when one leaves. Include a method for valuing a departing partner’s interest so no one argues over the buyout price later.
Intellectual property. If a partner is contributing patents, trademarks, software, or trade secrets, say whether that IP transfers to the partnership or is only licensed to it, and address ownership of IP created during the partnership.
Partnership representative. The person designated to deal with the IRS during audits and other tax matters.

Once the terms are settled, transfer them into a formal written agreement. Oral partnerships are technically valid in many situations, but they’re nearly impossible to enforce when the relationship sours. Many agreements include a clause requiring mediation or arbitration before either side can sue, which is faster and cheaper than a courtroom. Most states don’t require partnership agreements to be notarized, though notarization adds evidence that the signatures are authentic. Each partner should keep an original or certified copy.

Every partner also owes the others a duty of loyalty (no undisclosed conflicts, no competing with the partnership, no secret profits from partnership opportunities) and a duty of care (no reckless or intentionally harmful decisions). A partner who breaches either duty can be forced to give up any improper gains.

Register the Entity and Get an EIN

A general partnership needs no state filing to exist. An LP, LLP, or LLC does. The formation documents go to the Secretary of State or equivalent agency: a Certificate of Limited Partnership for an LP, Articles of Organization for an LLC.¹ Most states accept online filings; some still take mail or in-person submissions.

Filing Fees and Registered Agent

Total registration costs are typically under $300.¹ Every state requires LPs, LLPs, and LLCs to name a registered agent: a person or company with a physical address in the state who accepts legal documents, including lawsuits, on the business’s behalf. You can act as your own agent or hire a service, which runs about $49 to $300 per year.

Employer Identification Number

After your state approves the entity, apply for an Employer Identification Number from the IRS. The EIN functions like a Social Security number for the business and is required to file partnership tax returns, open a business bank account, and hire employees. Apply online at irs.gov for free; the IRS issues the number immediately on approval.³ The application asks for a responsible party and the business’s legal name as filed with the state.⁴

Doing Business in Another State

If the partnership operates in a state other than where it was formed, you may need to file for foreign qualification there. That means a Certificate of Authority and an additional filing fee. Skipping it can bring fines and cost you the right to file lawsuits in that state’s courts.¹

Handle the Tax Side

A partnership doesn’t pay income tax itself. Income, deductions, and credits pass through to the individual partners, who report their shares on their personal returns.⁵ You owe tax on your share whether or not the money was actually distributed.

The partnership files Form 1065 annually. For calendar-year partnerships, the deadline is March 15.⁶ An automatic six-month extension is available through Form 7004, but tax the individual partners owe is still due April 15. Along with Form 1065, the partnership issues each partner a Schedule K-1 showing that partner’s share of income, losses, deductions, and credits.⁷ Filing late costs $255 per partner for each month the return is overdue, up to 12 months.⁸

General partners owe self-employment tax on their share of ordinary business income plus any guaranteed payments for services. Limited partners generally do not owe self-employment tax on their distributive share, only on guaranteed payments for services they actually perform.⁹ Courts increasingly look at what a partner actually does rather than the title. A “limited partner” who runs the business day to day may still owe self-employment tax on the full share.

Because nothing is withheld from partnership distributions, each partner makes quarterly estimated tax payments to the IRS, generally required if you expect to owe $1,000 or more for the year.¹⁰ For 2026 the quarterly deadlines are April 15, June 15, September 15, and January 15 of the following year. Missing one can trigger underpayment penalties.

Plan the Exit Before You Need It

Even well-planned partnerships hit disagreements. The best moment to plan for one is before it happens, inside the partnership agreement.

A dispute resolution clause typically requires mediation first, then arbitration if mediation fails. Mediation is a neutral third party helping you reach a voluntary deal; arbitration produces a binding decision. Both usually run faster and cheaper than court. If the agreement says nothing about disputes, you default to whatever process your state’s partnership statute provides, which often means going straight to litigation.

A buy-sell provision sets the terms under which a partner can, or must, sell their interest to the others. Common triggers are retirement, death, disability, divorce, and voluntary withdrawal. The clause should say how the interest will be valued (an agreed formula, an independent appraisal, or a pre-set price) and how the purchase will be funded (business cash, installments, or life insurance proceeds).

If the partners decide to shut down, the partnership enters winding up: settle debts, collect what’s owed to the business, distribute what’s left, then file a dissolution or cancellation document with the state to formally end the entity.

Keep the Entity in Good Standing

Formation isn’t the last of the paperwork. Most states require LPs, LLPs, and LLCs to file an annual or biennial report with the Secretary of State along with a fee, commonly from around $50 to several hundred dollars. Miss the deadline and you can face penalties, lose good standing, or have the state administratively dissolve the entity, which strips the liability protection you formed it to get.

Keep your registered agent information current. If legal notices go to an outdated address and you never see them, you can default in a lawsuit without knowing it was filed.

1
U.S. Small Business Administration. Register Your Business
2
Cornell Law School / Legal Information Institute (LII). Revised Uniform Partnership Act of 1997 (RUPA)
3
Internal Revenue Service. Get an Employer Identification Number
4
Internal Revenue Service. About Form SS-4, Application for Employer Identification Number
5
Internal Revenue Service. About Form 1065, U.S. Return of Partnership Income
6
Internal Revenue Service. Publication 509, Tax Calendars
7
Internal Revenue Service. Partners Instructions for Schedule K-1 (Form 1065)
8
Internal Revenue Service. Failure to File Penalty
9
Office of the Law Revision Counsel. 26 USC 1402 – Definitions
10
Internal Revenue Service. Estimated Taxes