The timetable, the cost, and the two days nobody warns you about.
Aug 27, 2026
SPY flips Bull on the Markov read — and real NBBO data shows the fill assumption alone can flip an options backtest from profit to loss.
Aug 26, 2026
A Markov model says Sideways, the trend rule says Bull — both are right, and the difference is the lesson. Plus: how to keep a trading journal you'll actually use.
