I'm curious, how does the all-stock acquisition that closed 2.5 years ago affect their trailing P/E but not their forward P/E ?

Different accounting methods from what I gather. The acquisition is being accounted for over a 5 year period for the trailing p/e but not being included in the forward p/e over this 5 year period. This really shows how p/e is not a great metric in a vacuum.

Thank you all guys for the explanation. I was very puzzled seeing AMD p/e as a complete dilettante in finance reporting.