Michael Saylor, co-founder of Strategy, the world's largest publicly listed bitcoin holder, has a new term for Wall Street's most elite stocks and a congratulatory message for Elon Musk. Following SpaceX's historic Nasdaq debut Friday, the Strategy chairman took to X to congratulate Musk, noting that with SpaceX now public, 25% of what he calls the "Mag8" firms now hold bitcoin on their balance sheets.