What did I learn from selling the wrong stock?

The most heart-wrenching investment lesson has arrived. In 2014, I was a loyal fan of Amazon, and my investment tripled in three years. Then Bezos launched the Fire Phone, and I panicked—“This thing is definitely going to flop,” so I decisively closed all positions.

The facts have indeed verified - the Fire Phone was a historical flop. But this was the most expensive mistake I made: afterwards, Amazon's value increased 14 times. What I didn't realize was that for a founder-led company, failing a few times doesn't mean the direction is wrong. AWS, Prime, Whole Foods acquisition… these “strange ideas” later became cash cows.

Fast forward to now. I bought TransMedics (TMDX) at the beginning of 2023, a unicorn in organ preservation systems. Then the CEO suddenly announced the acquisition of Summit Aviation (an airline), and I panicked again—“this will collapse the gross margin.” The market also panicked, and the stock price was halved.

But this time I didn't sell. I remembered the lesson of the Fire Phone. I let the founder experiment because he has vision. Two years later, the CEO presented a complete picture of the national logistics network—the organ transportation capacity was fully maximized. Now TMDX has tripled from its low, sales have doubled, surgical volume has increased by 32%, logistics revenue has grown by 35%, and the net profit margin has reached 17%.

The key is: I was right about “airlines destroying profit margins,” but I was wrong not to see the overall upgrade of the business landscape. TransMedics is now aiming for 10,000 surgeries, and also plans to enter the kidney transplant and international markets—these could potentially be several times larger than the current business.

Buffett is right: learning from your own mistakes is good, but learning from others' mistakes is even more cost-effective. I am now continuing to increase my position in TMDX, the reason being to give the visionary founder enough time to prove themselves.