
{/* banner prompt: Cinematic realistic photograph, 16:9 wide banner composition: a close-up of a professional trading keyboard with a few colour-coded keys, a clear plastic safety cover hinged over one large key, a printed checklist on a clipboard beside it, crisp studio lighting. Muted teal and warm amber colour grade, soft natural light, shallow depth of field, high detail, photorealistic, no readable text, no numbers, no logos, no visible faces. */}

This is part fourteen of the [ASX order book series](/blog/2026/10/12-reading-the-asx-order-book-how-intraday-traders-actually-find-edge/) and the last post in the business-of-trading track. After [fewer trades, better months](/blog/2026/10/25-fewer-trades-better-months/), this one is about something less glamorous: making sure the trades you do take are executed the way you intended.

Reading the journals in full, I was struck by how many expensive days had nothing to do with market judgement. The read was right. The keyboard, the platform or the paperwork was wrong. These incidents showed up in every journal, at every level of experience. More experienced traders didn't stop making them entirely. They built systems that made them rarer and smaller.

<KeyPoints>

- Fat fingers, forgotten orders and wrong-side errors cost as much as bad market calls.
- Set maximum order sizes, use limit orders and reconcile your position after every fill.
- Arrange borrow before the auction and have a tested plan for platform outages.

</KeyPoints>

## The catalogue of execution errors

Here are the categories that came up, all of them more than once and in more than one journal.

<Table data={
    {
        headers: ['Error', 'How it happened', 'Typical cost'],
        rows: [
            ['Fat finger', 'An extra digit or wrong size field, sent at market', 'Can exceed a whole month of profit in seconds'],
            ['Forgotten order', 'An order left in pre-open or in the book, filled when no longer wanted', 'A position you never meant to have'],
            ['Wrong side', 'Thought the position was short, it was long, so the exit doubled it', 'Crossing the spread twice to fix it'],
            ['Wrong ticker', 'Similar codes, wrong one selected while rushing', 'A random position plus the cost of closing it'],
            ['No borrow', 'Tried to short in the auction without borrow arranged', 'Missed trade, or a rejected order at the worst moment'],
            ['Amending at the open', 'Changing an order as the stock opened', 'A fill far from the planned price'],
            ['Conditional order failed', 'A stop or contingent order did not trigger as expected', 'An unplanned overnight position'],
            ['Platform outage', 'Platform or app down on a busy morning', 'A missed day, or worse, stuck in a position'],
        ]
    }
} />

## Size guards: the most important setting you'll ever change

The single most expensive category was the fat finger. A trader means to buy 5,000 shares and sends 50,000, or 500,000. At market. In a thin stock. The fill walks up the book and the loss is immediate.

Defences, in order of importance:

<Steps>

1. **Set a maximum order size and value** in your platform and, if possible, with your broker. Make it slightly larger than your biggest normal trade, not ten times larger.
2. **Use limit orders, not market orders**, especially for exits in thin stocks. A limit a few ticks through the market gets you out fast without the risk of walking the whole book.
3. **Use preset size buttons or hotkeys** rather than typing quantities in a rush.
4. **Require confirmation above a threshold.** A pop-up you click through ten times a day is useless. One that only appears for unusually large orders is valuable.

</Steps>

## Hotkeys: speed with guard rails

Scalpers depend on speed. Several journals complained bitterly about platforms without good hotkeys, especially for the open, where a few seconds decide whether a trade is good or bad.

Good hotkey design:

- **Buy and sell at preset sizes** relative to the bid and offer.
- **Flatten** the current position instantly.
- **Cancel all** open orders in the current stock.
- **Join the bid / join the offer** for passive entries in front of protection.

Map them consistently, practise them in a simulator or with tiny size, and never map an aggressive market order to a key that's easy to hit accidentally.

## Reconcile after every action

The "wrong side" error happens when you lose track of your actual position. You think you're short, you hit buy to cover, and you were actually flat or long. Now you're long double.

The fix is boringly simple: **glance at your position window after every fill**. Make it big and visible on your screen. Some traders colour-code long and short positions so the state is obvious at a glance.

## Pre-open order hygiene

The opening auction creates its own class of errors, covered in the [opening auction post](/blog/2026/10/15-reading-the-asx-opening-auction/). The rules the traders converged on:

- **Write down every order you place in pre-open**, and cancel anything you've stopped watching.
- **Don't place "placeholder" orders** to hold a borrow or a queue position unless you're certain you'll manage them.
- **Don't amend aggressively as the stock opens.** Decide before the auction, or wait for the open and act on the result.
- **Limit the number of auctions you trade at once.** Trying to manage several matches in the same opening window produced some of the worst mornings I read about.

## Short selling and borrow

On the ASX, short selling of shares generally requires that you have arranged to borrow the shares, and brokers have their own rules and availability. For the opening auction, that means **borrow must be in place before pre-open ends**. On days when everyone wants to short the same sector, borrow can run out. Several traders described missing the best short of the day because borrow wasn't available, or because their broker's short limit had been reached.

Many active traders moved to **CFDs** for shorting, partly to avoid borrow friction. CFDs bring their own considerations: the provider's own short availability and limits, financing costs on positions held overnight, counterparty risk, and different tax and regulatory treatment. Read the disclosure documents and understand what you're trading.

## Plan for outages

Every journal had at least one morning where the platform, the data feed or the broker's app failed. Usually on a busy day, because that's when systems are most stressed.

An outage plan:

<Table data={
    {
        headers: ['Preparation', 'Why'],
        rows: [
            ['A second way to reach your broker', 'Mobile app, web platform or phone desk, tested in advance'],
            ['Stops resting at the broker, not only in your platform', 'They still work if your screen does not'],
            ['A backup account at a different broker', 'Lets you hedge or trade if one broker is down for a long time'],
            ['Small or no positions into known risk events', 'Less to manage if things break'],
            ['A rule for trading on mobile', 'Smaller size, simpler setups, or not at all'],
        ]
    }
} />

That last row came up a lot. Several traders traded from their phones during work or travel, and nearly all of them concluded that mobile trading should be at much smaller size, if at all. Their mobile days had noticeably more errors.

## The pre-market execution checklist

Before the open each day:

<Steps>

1. Platform, data and broker connection all working. Backup access tested this week.
2. Max order size and value guards set correctly.
3. Hotkeys loaded and sizes correct for today's plan.
4. Borrow arranged for any planned shorts.
5. Old orders from yesterday cancelled.
6. Position window visible and correct.
7. Today's watchlist and planned orders written down.

</Steps>

None of this makes you money. All of it stops you losing money you've already earned.

That ends the business track. Next, the series moves into psychology and development, starting with why the first couple of years of trading feel the way they do.

<SeriesNav series="asx-order-book" />

<Disclaimer />


6ce19e67ccac871f80f3050ea9ce5b1deccb7cb1d616a75deb8a36184a19a586

Practical execution hygiene for ASX day traders: hotkeys, fat finger protection, pre-open order checks, short selling borrow, CFDs and platform outage plans.

Some of the most expensive mistakes in the trading journals I read had nothing to do with market judgement: a fat-fingered order, a forgotten pre-open order, a short without borrow, the wrong ticker, a platform outage on the busiest day. A practical execution hygiene checklist for ASX day traders.

Tag: Execution

Tag: Execution

Execution Hygiene: Hotkeys, Size Guards and Borrow