The practice you described is illegal in just about every state in the U.S. and probably elsewhere. There's not a specific statute that prohibits ticket sellers from scalping their own tickets but it would clearly fall within most state's consumer protection statutes. It might even be a criminal act in some jurisdictions, but generally it will be a civil issue.
Illinois' consumer protection statute, 815 ILCS § 505/2, states that:
Unfair methods of competition and unfair or deceptive acts or
practices, including but not limited to the use or employment of any
deception, fraud, false pretense, false promise, misrepresentation or
the concealment, suppression or omission of any material fact, with
intent that others rely upon the concealment, suppression or omission
of such material fact, . . . in the conduct of any trade or commerce
are hereby declared unlawful whether any person has in fact been
misled, deceived or damaged thereby.
Illinois statute is similar to other state's consumer protection statutes as well. See this wikipedia article for a general overview of consumer protection law.
This basically means that it is unlawful to:
- Use deception, fraud, unfair acts, or conceal/hide material facts,
- With the intent that someone will rely upon the fraud/misrepresentation/deception/misstatement,
- In the course of any trade or commerce.
Addressing the Specifics of your Question:
Applying this law to your example, a company that buys tickets or reserves tickets that it is supposed to be selling to the general public and re-sells them on a website such as Stubhub.com, is conducting their business a misleading or even fraudulent way.
It is misleading and fraudulent because, assuming that they do not disclose to consumer that they reserve/sell large blocks of tickets to ticket re-sellers, consumers that try to buy the tickets from the original seller are deceived into thinking the tickets were actually sold out. This deception, by the original seller, causes them to try to buy the tickets through the re-seller (Stubhub) at an inflated price.
One can also make an argument that the the original seller is manipulating the market for the tickets to make it look as though they actually sold out, so they can inflate their profits. All of this is illegal because of the deception / lack of transparency. By itself, the practice of pricing tickets based on demand, not a fixed face-value, is legal. However, it is not often practice as the performer or sports team hosting the event would not receive the profits. Think of it this way--artists hate scalpers because they are taking away money that could go into their pockets and pricing out loyal fans.
Possible Proof Issues:
However, given the facts you have described above, I think you would have some difficulty proving a ticket seller was actually doing this. If you want to try to stop this practice, you should consult with a lawyer that can bring a private lawsuit against the ticket seller (unlikely to be an affordable option) or file a complaint with the Illinois Attorney General's office (they can, but are not required, to investigate your case).
It is more likely that the market is saturated with re-sellers. Many people make businesses out of buying and re-selling various tickets. Wired Magazine did an article on this practice in 2006 called Diary of a Scalper. I am sure that it has grown and gotten worse since the.
Laws Regulating & Prohibiting Scalping:
Also, here is an article from legalzoom.com that explains that scalping is regulated or illegal in some states; however, these laws are rarely enforced. Illinois is not one of these jurisdictions. https://www.legalzoom.com/articles/who-needs-tickets-is-ticket-scalping-legal