OK, what I understood from the article is that the guy owned 1% not of the company's acquisition price (as he thought), but 1% from (price - X) where X was unkn

OK, what I understood from the article is that the guy owned 1% not of the company's acquisition price (as he thought), but 1% from (price - X) where X was unknown and turned out to be greater or equal to the price. The fact that he didn't realize it until the very end makes the author's advise very correct - "make sure you understand exactly what you own".