Penson bet on the wrong horse (horse-racing track operator tied to one of its directors), which would be funny except for all the investor losses. Penson sold its clearing operations to PEAK6 Investments, which renamed it Apex Clearing Corp (not to be confused with TDAmeritrade's Apex).

Yes, TDA clears for itself with TD Ameritrade Clearing, Inc., an "indirect wholly owned subsidiary of TDA Holding Corp," although third parties are used for certain operations.

Yep, chills are related to clearing concerns. The question is whether these concerns can be manufactured.