[fxtentacle]

The article nicely explains this. They can buy up all competitors at inflated prices, which means they can hold the NHS hostage with its own data.

[josemanuel]

So can other companies! Once they spent all that money, what prevents other competitors from taking that business from them?

[felix_n]

They can simply not sell them. Palantir "buying" a company in this context means they either buy the owner out or buy controlling shares, in both cases nothing happens from there that they don't want to happen.