Yes, I understand a great many acronyms, and "...the stock is down 100% YOY..." would mean that the stock has gone to zero, which this one has yet to do. So, yeah, the remark did make make laugh out loud, because it was, well, not as true as you seem to believe.
I assume YOY means 'year over year', yes?
I feel smarter already.
Wait, now THAT's funny.