In a non-control deal, an investor cannot fire management. Therefore, the primary diligence focus must shift from the business itself to the founder's character and the potential for a strong partnership, as this relationship is the ultimate determinant of success.

Most technical problems discovered during diligence can be fixed. The real deal-killer is a loss of trust. When a company actively hides major issues, like a failed penetration test, it signals a fundamental dishonesty that makes a future partnership untenable, leading to an immediate abort.

To avoid disastrous partnerships, propose a radical transparency exercise. Each party agrees to hire a private investigator to vet the other, then discuss the findings. This surfaces red flags and demonstrates a commitment to honesty, saving years of potential pain.

An M&A advisor recounts a deal that collapsed just before closing when the buyer died in a plane crash. The critical lesson was advising the seller to not inform their employees prematurely. This prevented mass anxiety and operational disruption when the deal had to be restarted from scratch.

A prospect's unwillingness to introduce you to other decision-makers or share proprietary information (even under an NDA) is a definitive red flag. These are not signs of a slow deal, but of a dead one. It indicates a lack of serious commitment, and you should disengage to reinvest your time elsewhere.

An acquisition target with a valuation that seems 'too good to be true' is a major red flag. The low price often conceals deep-seated issues, such as warring co-founders or founders secretly planning to compete post-acquisition. Diligence on people and their motivations is more critical than just analyzing the financials in these cases.

In the Paramount/Warner bid, Larry Ellison's financial backstop used a revocable trust. This created a major risk for Warner, as the assets could be withdrawn at any time, potentially leaving them without recourse if the deal soured. This highlights a critical due diligence point in high-stakes M&A.

A deal with two founders was about to sign when the less-committed founder hired an independent valuation firm. The firm provided an unrealistically high valuation, which he used as justification to kill the deal. Acquirers should address founder reluctance early, as emotional attachment can override a logical deal process.

Waiting until just before closing to present employment and equity documents to the management team creates distrust and feels like a power play. To maintain a true partnership, buyers should outline and agree upon these critical terms much earlier in the process, ideally via a term sheet before the final docs.