Every trade runs on machinery: the order you send, the rules that govern trading, the auctions that open and close the day, and the expiration mechanics of options. This hub maps all of it — the plumbing that turns a decision into a filled, managed position.
Order types: getting in and out
- Market order: speed over price
- Limit order: price control
- Marketable limit: the scalper's sweet spot
- Mid-price order: splitting the spread
- Stop order: your automatic exit
- Stop-limit: a stop with price control
- Stop-market vs stop-limit: which protects you
- Trailing stop: following your winner
- Bracket order: entry, target & stop in one
- OCO: one cancels the other
- Market-on-close (MOC)
- Limit-on-close (LOC)
- Day order vs GTC
- Fill-or-kill, AON & IOC
- Marketable vs non-marketable
- How to place a limit order (step by step)
Halts & circuit breakers
- What are circuit breakers?
- Level 1, 2 & 3 circuit breakers
- Market-wide vs single-stock breakers
- What is a trading halt?
- What is LULD?
- Limit up / limit down
- What if SPY is halted while you hold 0DTE?
- The short-sale restriction (SSR)
Auctions & the close
- The opening auction
- The closing auction
- What is an order imbalance?
- The MOC imbalance: a late-day tell
- Why the close is so volatile
- What is max pain?
Assignment, exercise & expiration
- Early assignment explained
- Exercise by exception (auto-exercise)
- Assigned by a penny
- What is pin risk?
- Can assignment cause a margin call?
- European vs American-style options
- Do SPY options trade after hours?
- Holiday & half-day schedule
Market plumbing
- The NBBO: best price across exchanges
- Payment for order flow (PFOF)
- What is price improvement?
- What is a market maker?
- What is the Cboe?
- What is a block trade?
NoVo maps every dealer level across SPY, QQQ & IWM and shows what its own record says that setup has done before, with the sample size built in. See Trader · Crypto, Analyst, or compare plans.
Why this matters
You don’t need to master every detail here, but the difference between a trader who understands this machinery and one who doesn’t shows up in fills, in exits, and in not getting blindsided by a halt or an assignment. Every one of these decisions is yours to make at your own broker, which is exactly why knowing what’s under the hood pays. Start anywhere above.