Signing and closing are 2 distinct moments in a financing or acquisition. Signing is when the parties execute the definitive agreements and commit to the deal on agreed terms. Closing is when the conditions in those agreements are satisfied and the transaction actually completes, shares issued, money wired. In many venture rounds the two are simultaneous or close together, but they can be separated by days or weeks, and that gap is where deals still fall apart even after everyone has signed.
The gap exists because the signed agreement usually lists conditions precedent, things that must be true or done before closing is obligatory. Common ones: completion of confirmatory due diligence, delivery of clean IP assignments, required third-party or regulatory consents, board and shareholder approvals, no material adverse change in the business, and sometimes the achievement of a specific milestone. Until those conditions are met (or waived), the money is not owed, and a party can walk if a condition fails. Earlier, the term sheet itself is mostly non-binding, so “signed term sheet” is even further from cash than “signed definitive agreements”.
For a deep tech founder the practical rules are 2. First, plan runway to the close, not to the signature: a company that lets cash run to zero on the assumption that a signed deal equals money in the bank can be caught if closing slips or a condition bites. Second, work the conditions down early, especially the ones a deep tech company is prone to, the university IP chain and licenses, technical verification, key consents, because they are exactly the items that take time to clear and that a buyer or lead can use to re-trade or delay. Treating the deal as real only when the wire arrives, and managing the conditions actively in between, is what keeps the gap between signing and closing from becoming the place the round dies.