it's a mistake to only consider (perceived) market share (100%, 51%, or otherwise) as the primary metric of monopoly. it is, in fact, only one metric of many by which monopoly is judged.

being a platform business that competes directly with its business customers can be a significant (but not necessarily sufficient) indicator as well.

>it's a mistake to only consider (perceived) market share (100%, 51%, or otherwise) as the primary metric of monopoly.

It is according to US law. Without a larger percentage, no court will consider anti-trust charges, due to Circuit and Supreme Court cases on what percentage of market control is required. Here's relevant portions from DoJ:

"In determining whether a competitor possesses monopoly power in a relevant market, courts typically begin by looking at the firm's market share.(18) "

So the typical case starts with percent control....

"Although the courts "have not yet identified a precise level at which monopoly power will be inferred,"(19) they have demanded a dominant market share"

So the courts require a threshold.....

"the Tenth Circuit noted that to establish "monopoly power, lower courts generally require a minimum market share of between 70% and 80%.""

There's ample more court citations on the DoJ page.

Amazon doesn't reach these levels in probably any relevant category they are in. Certainly not for retail sales (Amazon is a tiny portion there), or online sales (less than half), or web services (Amazon ~ 40B out of 350B market).

For any company, if you shrink the categories far enough, you can always find a monopoly - Apply has a (near) monopoly on Apple watches, for example. But this is not a monopoly.

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

I don't know exactly what US anti-trust law says, but German anti-trust law also considers what kind of power you have over competitors and suppliers to decide whether you're behaving anti-competitively. We call it (roughly translated) "Law against constraint of competition". Amazon might qualify as abusing their position under our laws. Unfortunately, it can be difficult to get a case started if the relevant authority isn't paying attention because of how the justice system is structured here and there's a question of how badly companies are actually being impacted in Germany by Amazon's behavior. Our wholesale/retail market seems to be a bit different and far more diverse than in the US.

yes, we have similar kinds of rules, but i imagine the ones in germany have a little more tooth. we in the US just can't seem to punish corporations adequately for any antisocial behavior.