Any partner can usually sign a deal that looks like the business's ordinary business and bind every partner to it, without asking first and without anyone's permission. That is not a loophole; it is the basic design of a general partnership. The Uniform Partnership Act (1997) makes each partner "an agent of the partnership for the purpose of its business," and an act that apparently carries on the partnership's ordinary business binds the partnership even if the other partners never heard about it until after the fact (section 301(1)).

The word doing the work in that sentence is "ordinary," and the line between an ordinary deal and one that needed everyone's sign-off is narrower, and less intuitive, than most partners assume before it costs them. This is general information, not legal advice for a specific transaction; a lawyer in the partners' state should review a spending-limit clause before it is relied on.

Ordinary course versus everything else

Section 401(j) draws the line the statute actually uses: a disagreement over a matter in the ordinary course of business is settled by a majority vote of the partners, but an act outside the ordinary course, or any amendment to the partnership agreement itself, requires every partner's consent. Combined with section 301, the practical rule is this: a partner acting alone can bind the firm to anything a reasonable outside party would read as ordinary for a business like this one, and cannot bind the firm to anything that looks unusual, large, or outside the business's normal activity, unless the other partners already agreed to it.

The trouble is that "ordinary" is read from the other party's point of view, not the partners' internal understanding of their own roles. A hardware store's ordinary business plainly includes ordering inventory and paying the electric bill; it just as plainly does not include selling the building. Between those two extremes sits a wide gray zone: signing a two-year equipment lease, hiring a $90,000-a-year employee, taking out a line of credit. None of those is obviously ordinary or obviously extraordinary from the outside, which is exactly why a partner with no stated limit can bind the firm to any of them, and why the other partners' private understanding that "we don't do that without talking first" protects nobody who was not a party to that understanding.

What limits a partner's authority, and who it protects

Inside the partnership, the only real protection against a partner who oversteps is a written limit the partners actually agreed to and, ideally, told the people they regularly deal with about. A written agreement that caps what any one partner can commit to without a co-signature is enforceable between the partners regardless of whether it is also filed publicly, though an outside party who had no notice of the limit and dealt with the partner in good faith can still bind the firm under section 301's ordinary-course rule. The limit changes who is liable to whom afterward; it does not always stop the deal from existing in the first place.

For an LLC, the default runs the other way

A multi-member LLC does not inherit this rule automatically. Under the harmonized uniform LLC act, a member is not an agent of the LLC "solely by reason of being a member" (section 301(a)), which flips the partnership default: where a partner can bind the firm until the agreement says otherwise, an LLC member generally cannot bind the LLC until the operating agreement, a resolution, or ordinary agency principles say they can. A member-managed LLC's operating agreement usually grants that authority back to each member for ordinary matters, but it is a grant the agreement makes, not something the member already had by virtue of membership.

A spending-limit clause

Sample authority and spending-limit clause 
Authority to Bind the Partnership. Each Partner may act alone to bind the Partnership to any contract, lease, or purchase in the ordinary course of the Partnership's business involving a dollar amount, individually or cumulatively with related transactions, of less than $[__]. Any contract, lease, purchase, loan, or other commitment at or above that amount, and any action outside the ordinary course of the Partnership's business, requires the prior written consent of all Partners (or, if the Partners have so agreed, a majority of the Partners by capital interest). The Partnership shall notify its bank, landlord, and principal suppliers in writing of this limitation and shall promptly notify them in writing of any change to it.

The dollar figure is the whole clause; too low and every ordinary purchase needs a second signature, too high and it protects nothing. The notice sentence matters more than it looks: a limit nobody outside the partnership was ever told about still leaves a partner able to bind the firm to a third party who had no reason to know the limit existed.