Market Structure.

A stock drops 10% and suddenly your short order won't fill at the bid. How SEC Rule 201 works, how long it lasts, and what it doesn't touch.

Your ES or MES order won't fill below a certain price, and nothing is broken. Here is how CME's 7%, 13% and 20% limits work, hour by hour.

Price hit your level and your order sat there. On a FIFO exchange that's the system working as designed. Here's the mechanic, and what it does to backtests.

The COT report shows Tuesday's positioning every Friday. A peer-reviewed backtest found the edge mostly disappears once you try to trade it.

A stock closing dead-on a strike price at expiration isn't luck. Dealer hedging pins it there, and it can leave you holding shares you never planned to own.

A halted stock doesn't reopen where it paused, or at a random price. Nasdaq's July 2025 rule finally capped how far that first print can move.

Nasdaq's own rule filing blocks market orders after 9 PM and cancels whatever's still open at 4 AM. Here's what the night session actually allows.

CME hiked gold and silver futures margin three times in three weeks in early 2026. What actually changed, and what it means before your next leveraged trade.

CME rolls on the Monday before the third Friday. Your chart switches on a different rule entirely. The gap between those two dates is where levels break.

Nvidia funds OpenAI, OpenAI buys Nvidia chips, the stock lifts on the revenue. A walk through the AI circular revenue loop and what probably survives.