[nabla9]

In articles like this monopoly is used as shorthand for monopoly power.

For a company to have a 'monopoly power' it does not have full monopoly. Antitrust laws start to apply to corporations long before they have full monopoly.

[ucaetano]

> monopoly is used as shorthand for monopoly power

No, it is used as shorthand for "market share in a market I define arbitrarily".

Proving monopoly power is a much more complex and academic process.

[nabla9]

Antitrust law is based on it.

You can read here how it is defined and identified in practice.

https://www.justice.gov/atr/competition-and-monopoly-single-...

[ucaetano]

Yep, and from the link:

The Supreme Court has defined market power as "the ability to raise prices above those that would be charged in a competitive market,"(8) and monopoly power as "the power to control prices or exclude competition."

Those are the tests you need to pass to take action. And measuring that is a highly academic exercise.

Just go talk to the economics professors and consultants that act as experts in those cases.