Although we suppose he could have gone with fellow sociopath "Tailgunner Ted" Cruz just as easily:
@JebBush i'm an avid supporter— Martin Shkreli (@MartinShkreli) February 6, 2016
Don't know whether this is a less desired "endorsement" than the white supremacists' "endorsement" of Donald "Rump" Trump, but it's close.
UPDATE: It sounded too good to be true. Now he's saying it was all a joke.