Doing a backtest I stumbled into a security called "CDII" which has a very weird price change between 2008-09-19 and 2008-09-22, moving from 0.05 to 5.51 (interpreted as a huge gain on that day, see attached backtest). I looked at yahoo and other sources and while it looks like an extremely volatile security that is basically worth nothing today, but back in 2008 it had some value. I'm wondering if there was a split those days that was not correctly documented in the quantopian system?
Thanks
Karol