That's the bet-swap. They have both have a contractual obligation to exchange investments in each other. It's a suicide pact OR it's a bromance glow-up, depending on your point of view. AMD is giving them chips on the (accurate so far) bet that buying chips will inflate AMD's stock value.

Again, this is not a thing a rational person would do because it's both not sustainable and not realistic unless you expect the value of everything to got up for 10+ years. It's a recursive bet on a bet on a bet. It's like buying T-bills.