Instead of using behavioral questions in initial calls, Salas O'Brien views the entire three-month diligence period as the real interview. How a target's leadership responds to the inevitable challenges that arise reveals more about their character and working style than any prepared answer could.

Standard reference checks yield generic praise. To identify true A-players, ask their former colleagues a high-stakes question: “Would you quit your current job to work for this person again?” An enthusiastic “yes” is the strongest hiring signal you can get.

During diligence, speak directly with the target's largest clients. You may uncover deal-breaking risks, such as a client who will leave post-acquisition because their internal rules prevent reliance on a single, monopolistic supplier, a fact you would otherwise miss.

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.

A key part of buy-side M&A is conducting 'reverse diligence,' where the buyer transparently outlines post-close operational changes (e.g., new CRM, org charts). This forces difficult conversations early, testing the seller's cultural fit and willingness to integrate before the deal is finalized.

The most effective due diligence involves finding franchisees not on the franchisor's reference list and asking them one key question: 'Knowing everything you know now, would you do this again?' Their unfiltered answer provides a clear signal about the business's true challenges, profitability, and franchisor support.

Interviews can be misleading as founders are skilled at presenting well. Venture investor Naveen Chaddha relies heavily on extensive back-channel references to create an "X-ray" of a founder's history. He believes that while founders can craft a narrative, they cannot hide from their past actions and reputation.

Instead of only the buyer investigating the target, successful M&A involves "reverse due diligence," where the target is educated about the buyer's company. This transparency helps the target team understand how they will fit, fostering excitement and alignment for the post-close journey.