> A rule of thumb is that if you own more than 50% and can dictate prices, you might be a monopoly. I guess the UK has different laws, but here in the US it wo

> A rule of thumb is that if you own more than 50% and can dictate prices, you might be a monopoly. I guess the UK has different laws, but here in the US it works like this: * 50% and below means you are definitely not a monopoly unless there is some weird set of facts than SCOTUS couldn't imagine the last time they considered monopolies. * At some threshold around 60-70% you might be a monopoly, but market share alone isn't enough to prove that. * Around 90% you are presumed to be a monopoly unless you can provide some very good evidence why you are not.