A few years ago, my French Polynesia stamp club tried to corner the market after spending years being defensive. For the first time, the club launched an offensive attack by monopolized a specific target. That specific target was French Polynesia's 1969 Napoleon stamp sheet. These sheets were vulnerable because only a few dozens survived. Some were discard & some were accidentally ruined by collectors. To make things worse, a fire broke out at a stamp shop that destroyed several sheets. The sheet couldn't be seen in the public, private or even in the black market.
After 32 years of disappearance, two sheets suddenly appeared at a private auction in Paris - the only two sheets exist on Earth. In auction, our stamp club outbid everyone & won both sheets. Some of our members were upset because they weren't consulted. Some were disgusted because there were no election or meeting. I was dismay because I dislike monopoly. In 2017,a Frenchman came forward with a sheet - the third sheet in the world. I was happy & hopefully there are more sheets somewhere out there.
Napoleon stamp in MNH ($55 - $95)
French Polynesia Stamp Club