[mushufasa]

Well, maybe you could think about it like this:

If they don't intervene, they lose all their previous investment guaranteed. So just consider all of that previous investment gone (sunk cost).

If they invest $5b they may make an $8b valuation. And they may still think there is upside beyond that.

Not sure if that's what they really think, but a lot of posters here seem to accuse softbank of sunk cost fallacies without considering that they are surely aware of investing 101.

[goatinaboat]

The sunk cost fallacy has a name because people keep doing it, even knowing what it is