When you buy a company, the financial review gets most of the attention. The technology often gets a few slides near the end. But the systems, the software, and the people who run them are part of what you’re paying for, and they can be the most expensive surprise after closing.
Bankers feel this too. In a survey published in 2026, covering 150 senior executives at US investment banks, 51% called technology diligence the most burdensome part of the review (SRS Acquiom).
Getting the basics right starts with five questions, asked early enough that the answers can still change the price or the plan. Each question below comes with a lesson from a real deal, some that worked and some that went wrong.
1. Which systems actually run the business?
Ask for a plain list of the systems the company depends on every day: finance, sales, operations, and anything customers touch. Then ask who owns each one. Is it licensed, built in-house, or run by an outside vendor? A company can look modern on the surface and depend on one old system underneath.
2. What’s old, unsupported, or fragile?
Every company has some technology it has put off fixing. That’s normal. What matters is how much, and what it will cost to fix. Look for software that’s no longer supported, systems that only one person understands, and projects that were started and never finished.
3. How secure is it?
Ask whether the company has had a breach, when it last tested its security, and who is responsible for it. The same survey found that 84% of bankers expect more scrutiny of cybersecurity in diligence over the next one to two years. A security problem you inherit becomes your problem the day the deal closes.
Lessons from real deals: after Verizon agreed to buy Yahoo’s core business in 2016, Yahoo disclosed two massive data breaches. The deal closed, but for $350 million less, with the two companies splitting some of the legal costs (CNN Money). Marriott wasn’t as lucky: a cyberattack on Starwood’s reservation system began in 2014, before Marriott bought it in 2016, and wasn’t detected until 2018. Marriott said it had only been able to do limited diligence, and UK regulators fined it £18.4 million (Mayer Brown). Found before closing, a security problem is a negotiation. Found after, it’s your bill.
4. Who keeps it running?
Technology runs on people. Find out which two or three people the key systems depend on, whether they plan to stay, and what’s written down versus what lives only in someone’s head. Research from MIT Sloan found that a third of employees at acquired startups left within the first year (MIT Sloan). The people you’re counting on may not stay unless you plan for it.
A lesson from a deal that worked: when Disney bought Pixar in 2006, it wrote the people plan into the deal. Pixar kept its name and headquarters, its leaders ran animation at both studios, and a steering committee was set up partly to maintain Pixar’s culture (SEC filing).
5. What will integration really take?
At some point, the two companies’ systems have to work together, or one has to replace the other. Ask which systems overlap with yours, which contracts can be ended, and what the first 90 days after closing will need. A rough plan before you sign is worth more than a detailed one after.
A lesson from a deal that went wrong: after Banco Sabadell bought TSB in 2015, the plan was to move TSB’s customers onto Sabadell’s banking platform. When the move happened in April 2018, the new platform failed almost immediately, and many customers had trouble banking until December. TSB paid £32.7 million in compensation and was later fined £48.65 million (Morgan Lewis). The plan existed, and so did the budget. What it needed was testing as if the business depended on it.
What to do with the answers
Some answers will be reassuring. Others will point to costs or risks that belong in the price, the terms, or the integration plan. Either way, you’ll be making the decision with your eyes open.
I’ve been on the buying side, the selling side, and the cleanup after the deal. As the first Global CIO of Foundry (IDG), I helped lead 4 acquisitions in 18 months. Through Bishop CheckMate, I help mid-market CEOs and executive teams answer these questions before they sign.
If you’re weighing a deal, let’s have a conversation.