Why I Turned Down an Acquisition Offer Worth Hundreds of Millions

The email came in on a quiet Sunday evening.

It was the kind of message every entrepreneur dreams of receiving — an acquisition offer.

The number was so large, and the screen so small, that I had to zoom in. Then zoom out again.

Hundreds of millions. A life-changing figure.

I put my iPhone down. My hands were cold. I walked to the window. I needed time to think.

I should have felt excitement. Relief, even.

I just stood there. Shivering.

Two options

If I said yes, everything would change. The company I'd built. The people who had trusted me. The mission that had driven me.

For years, I'd fought to stay independent — to prove that scaling fast and staying profitable weren't mutually exclusive.

Now I had two options: take the money and walk away. Or bet on myself one more time.

It was the peak of a biotech boom. Private equity firms and global corporations were circling. Valuations were soaring. Everyone wanted a piece of what we'd built.

The offers were massive. Hundreds of millions.

What the money would have cost

I pictured myself sitting across from financial investors. Watching them optimize for short-term returns. Cutting R&D to hit next quarter's numbers. Prioritizing spreadsheets over impact.

My stomach turned.

I wasn't about to hand over my life's work to someone who saw it as just another asset to be optimized.

There was no playbook for this moment. No guide. Just sleepless nights and red eyes.

Founders who turn down acquisition offers rarely talk about what that decision actually feels like in the moment — the doubt, the second-guessing, the fear that you're making the biggest mistake of your life.

I had to ask myself questions I'd never really asked before. What did I actually want? What made me satisfied? Was it the money? Would I be happy as a multi-millionaire - or even a billionaire?

I didn't know. But I knew enough to know that selling wouldn't answer those questions. It would just postpone them.

Why I Turned Down the Acquisition Offer

I turned the offer down.

To put it in perspective: not long after, the same company acquired a similarly sized competitor for 1.4 billion dollars.

I think about that number sometimes. Not with regret — with clarity. Because that number was never really the point.

Where I came from

I'm the son of a kindergarten nurse and an electrician, from a 250-person village in Bavaria. Hundreds of millions is not a number you say no to lightly. For someone like me, that kind of money doesn't just change your bank account — it changes who you are, who calls you, how people see you, and how you see yourself.

Maybe that's exactly why I had to say no. Because I knew what saying yes would cost — not financially, but in everything that actually mattered to me.

Why I'm telling you this now

That Sunday evening, that one quiet decision, became the moment my book began.

Not because turning down money makes a good story (though I suppose it does). But because that evening forced me to articulate something I'd been living by without ever putting into words: a set of principles for building a company — and a life — that you don't want to walk away from.

I call it the Code of Honor. It's the backbone of everything I've learned over 19 years of building NanoTemper — from a benchtop prototype in a university basement to a €56M, 100% founder-owned company operating in more than 60 countries.

Ein ehrbarer Entrepreneur, the German edition of my book, is published on July 13 and available from July 23. It's part memoir, part manifesto — the real, unpolished story of building something that lasts. No investors. No exit. Just proof that scale and integrity can coexist.

If you've ever stood at a crossroads where the easy choice and the right choice weren't the same thing — I wrote this for you.

What's your number?

Not everyone gets an offer like mine. But almost everyone, at some point, faces a version of this question: take the easier path, or stay true to what you actually set out to do.

What would it take for you to say no to your number?

If this resonated with you, I share more stories like this - about building NanoTemper, staying independent, and the Code of Honor - every two weeks in my newsletter -> subscribe to my newsletter