Fund flow tracking: $OGN plunged 4.62% in 15 minutes.
To figure out who's selling, I usually watch two things:
· Are there consecutive aggressive sell orders during the drop?
· Are there large buy orders stepping in after the price falls?
For reference: 24h trading volume was $63.5 million, up 93.71%. If both are present, it often means a change of hands; if only the first is, watch out for more selling pressure.

Whether to buy is up to you. I'm just keeping a record.