Whoever Kight had accumulated those shares for evidently has taken over control of them. I doubt they bought them up to that level and then just dumped them back on the market. We may be getting close!!
MSTF...the filing means that Knight has sold most of its shares in this company.
You will see them on bid and ask as they handle orders electronically for others. For example, most of my buys and sells show up as NITE in my regular trading account. Some of my trades in my IRA account show up as NITE.