What actually forces a deal to move to a definitive agreement after an LOI?

Nothing legally forces it, in most cases. Because the core terms of an LOI are typically non-binding, neither party is usually obligated to actually sign a full purchase agreement just because an LOI exists — what moves a deal forward is both sides remaining willing, due diligence coming back clean enough, financing coming together, and the terms still making sense once everyone has looked closer. A court generally won't order a party to complete a sale, or even sign a definitive agreement, simply because an LOI was signed.

The exception, and it's a narrow one, is if the LOI itself contains an express obligation — for example, a genuine commitment to negotiate a definitive agreement in good faith. Even where that kind of clause exists, courts are typically cautious about enforcing it as anything more than a duty to negotiate honestly, not a duty to actually reach or sign a final deal on particular terms.

If you're relying on an LOI to feel confident a deal will actually close, that confidence should come from the underlying business fundamentals and the other side's genuine motivation, not from believing the document itself compels anyone forward. A Treadstone business lawyer can help you read your specific LOI for exactly what, if anything, it actually requires.