There is another way to corner the market on a certain stamp issue. This one is easier and has been tried in the past too.
Suppose the small country of Upper Philatelica decides to issue a souvenir sheet. They print 10,000 of these souvenir sheets.
Instead of selling them through normal channels, the postal administrator approaches a dealer (or the dealer approaches the postal administrator). They agree that the entire supply of souvenir sheets will be sold to the dealer at a fixed price.
The dealer now has the entire supply of souvenir sheets. Do you want a copy for your collection? Youíre going to have to pay his retail price because he is the only one that has them. The key is to charge a high price to make a large profit. But you canít price them too high or youíll drive customers away.
This partly depends on the popularity of the country too. If itís a tiny country and there are not that many collectors who are interested in that country, itís going to take a while to move those souvenir sheets. And you donít want to buy, say, 100,000 souvenir sheets if you think the number of collectors interested in them numbers in the few thousands. What are you going to do with the other 90,000 copies?
There is one caveat though. What if the country decides to print more of the souvenir sheets and sell them in normal postal channels? The dealer just got taken! What is he going to do Ė sue the postal administration and reveal the illegal business agreement they had to buy the initial supply? Good luck with that court case. Assuming it goes to trial and the dealer is successful, itís too late. The postal administration has probably sold thousands of copies of the second printing anyway.
The advantage to the dealer here is that they can corner 100% of the supply in a single financial transaction. The disadvantage is that they need to pay for the whole stock at one time. And there is the risk that the postal administration goes behind their back and issues other souvenir sheets anyway.