I can't believe I'm saying this, but you might be right about the SGP mixup. I mean... it makes NO sense, and you probably meant it as a joke, but how else do you explain a 10% jump on no news with double the average volume (which seems to be near an all-time record)?
Name mixup could be the reason. STEM is up 43% today on news that embryonic stem cells are OK. I think it's the name because they don't even use embryonic. They use adult stem cells. Momentum lemmings shoot from the hip and ask questions later.