Like storing gasoline to create an artificial demand and sell it a higher price later.
'Hoarding' is the word that comes to my mind. That at least covers the storage of scarce resources, but I'm not sure if it is really the right word to include selling it at a higher price.
How about 'Price-fixing'? That would be a collection of 'competitors', artificailly increasing the price by some means (possibly by limiting supply).
Profiteering can be used here.
From Cambridge Dictionary:
profiteer (noun): a person who takes advantage of a situation in which other people are suffering to make a profit, often by selling at a high price goods which are difficult to get.
The pharmaceutical company has been charged with profiteering from the AIDS crisis.
From Oxford Dictionaries:
profiteer (verb): make or seek to make an excessive or unfair profit, especially illegally: seven food merchants were charged with profiteering.
This is the very definition of "cornering the market."
Cornering the Market is the best term if you're actually buying so much of the item that prices go up. It rarely happens.
Stockpiling implies that you're stocking up on something, without necessarily implying that you plan to profit from that.
Profiteering is simply a value-laden term for increasing prices when demand goes up.
Hoarding implies keeping a disproportionate share of something for oneselve, not necessarily for profit.
As I stated in a comment earlier to moioci, "cornering the market" merely means having complete control of it, not necessarily by hoarding a commodity.
A few examples, quickly found:
- Dell set to corner the market for desktop virtualization hardware
- Apple trying to corner market on location-based advertising?
- Is a Silver Market Corner Underway?
- Romero's Undead Island Trying To Corner The Market On Water Zombies
- Will Microsoft Corner the Desktop Security Market?
My "source" is obvious: widespread, common usage. The definition given in Wikipedia is a narrow one applying to a specific domain. The term has much much broader use. Please, people! Wikipedia is not the holy scriptures! At least look a little bit further!
The proper answer would be a combination of all the terms Joel mentioned:
"Hoarding and Stockpiling with an intention to Profiteer and Corner the Market". I know of no single word in English for this, but "Cornering the market" is not it. Perhaps you could assemble one in German?
Arbitrage is a related term for taking advantage of difference in prices, and may include storing something for later sale. For instance, if the arbitrageur can secure storage for less than the difference in price between buying today and a contract for sale in the future. This might occur when the market is expecting the price of the commodity to increase dramatically, and therefore prices for future contracts are still high.
However, it does not relate to trying to increase demand by lowering supply.