Guide 4.4
Intermediate, 7 min read. Checked with Scalpel 1.12.8 on .
In short
Every Scalpel buy is a marketable limit: a limit order priced at the ask plus your Buy offset (10 cents by default), so it fills straight away against what is offered but never pays more than that cap. Anything the book cannot fill up to the limit keeps working at the limit as a partial fill, until it fills, you cancel it with Ctrl+Q, or you sell out. Buys and sells are blocked while the US market is closed (before 04:00 or after 20:00 ET, weekends and holidays), and buys while the stock is halted.
A marketable limit is how momentum traders get in fast without handing the market a blank cheque. A plain market order on a thin small-cap can fill dollars above where you pressed; a limit right at the ask can miss the move entirely. The ask plus a few cents is the middle ground, and outside regular hours it is the only kind of order the exchanges accept anyway.
Before you start
When you press a buy key or button, Scalpel does this in one go:
Worked example: ABCD offers 245 shares at 5.71, 1,000 at 5.72 and 2,000 at 5.73. You press Risk $200 with a 30c stop: 666 shares, limit 5.71 + 0.10 = 5.81. The order takes the 245 at 5.71 and 421 at 5.72, an average of about 5.716. It never touches a price above 5.81.
The offset is your slippage budget, not a price you pay: you fill at the prices on the book, up to the limit.
The buy and sell offsets are on the order bar (Offset steppers, 10c a click, never below 0) and in Settings > Trading as Buy offset (c) and Sell offset (c). Both places change the same saved value, for every desk.
| Offset | Good for | The catch |
|---|---|---|
| 0c | Paying no more than the ask you saw | Misses the fill when the ask lifts as you press, leaving a partial or nothing |
| 5c to 10c (default 10c) | Most $2 to $20 momentum stocks | You can pay up to that much over the ask on a thin book |
| 15c to 30c | Fast breakouts on pricier stocks | A large order can walk deep into the book |
If the book runs out before your limit, you get what was there and the rest keeps working at the limit, like a real resting order.
The Orders tab shows a working buy as Partial, with the average fill so far. Your stop and take-profit arm on the first fill. When more shares fill, the levels stay exactly where they are (including a stop you dragged); only your average moves, so breakeven (guide 5.3) then means the new average. Adding shares with a second buy works the same way.
The rest stops working when:
In LIVE, a scale-out (1/2, 1/4) leaves a working buy alone, so cancel it yourself with Ctrl+Q if you do not want it.
Scalpel trades the pre-market (from 04:00 ET), regular hours and after-hours (to 20:00 ET; 17:00 on early-close days). Outside those hours, at weekends and on market holidays, there is no real liquidity, so entries and exits are blocked:
Extended-hours fills in Settings > Trading (on by default) decides whether your LIVE buys may fill outside regular hours. Turn it off and Interactive Brokers only fills your LIVE entries between 09:30 and 16:00 ET. Exits are not affected: stops, targets, sells and Flatten All always go out allowed to fill outside regular hours. SIM ignores the switch. See guide 13.13 if the bar is grey when you think it should not be.
While a stock is halted, its desk shows a HALTED banner, the buy buttons are grey, and a buy key is refused with ABCD is halted: buys are blocked until it resumes and the voice "Rejected.". A halted stock usually reopens with a gap, so no entry may queue up for the reopen. Sells and Flatten All are not blocked, but nothing trades until the halt lifts.
Each refusal shows as a red toast and the voice says "Rejected.":
| Message | Why | Fix |
|---|---|---|
| No market data yet | The desk has no book yet | Wait for Level 2 to fill in |
| No ask to price against | The book has no offers | Wait for offers to show |
| ABCD is halted: buys are blocked until it resumes | Trading in the stock is halted | Wait for the halt to lift |
| Order size resolves to zero shares | The preset sizes to under one share | Raise the risk or tighten the stop |
| Order exceeds the fat-finger cap ($...) | The order is over your fat-finger cap | Guide 7.2 |
| Position would exceed the max ($...) | It would take the symbol past your max position | Guide 7.2 |
| Insufficient buying power: order $... exceeds free cash $... | SIM is a cash account | Smaller size, or raise SIM start in Settings > Risk |
| Risk locked: ... | The daily loss limit has tripped | Guide 7.1 |
| No liquidity for ... | SIM: nothing on the book up to your limit | Raise the offset, or wait |
A LIVE order can also be refused by Interactive Brokers itself, for example for buying power; see guide 13.5. If the intel dilution guard is on and the stock has a fresh dilution flag, the first press only warns and you press again within 4 seconds to confirm (guide 9.7).