You're about to send an order. The form asks you to choose between "limit" and "market". These two options are the most frequent — and most misunderstood — decision in a retail investor's life. Here's what concretely changes between them and how to decide cleanly each time.
Market order: execution guaranteed, price isn't
A market order fills immediately at the best price available on the order book the moment it's processed.
Pros
You're sure to fill (at least for the quantity available). No waiting: filled in milliseconds. Handy to close a position quickly when the market moves hard.
Cons
- Variable price: if liquidity is thin, your order can "eat" several levels of the book and end 1-2% higher (buying) or lower (selling) than the quoted price.
- No cap: on a volatile name, the fill price can be very different from what you saw 2 seconds before clicking.
- Avoid at the open: the first orders often pay the highest price for opening-fixing volatility.
When to use it
On a very liquid stock (top MASI names: ATW, IAM, BCP…) where the spread is tight. When you must exit right now (bad news, urgent cash need). For small quantities on liquid stocks.
Limit order: price guaranteed, fill isn't
A limit order only fills if the market reaches the price you set.
- Buy: fills at your limit or lower.
- Sell: fills at your limit or higher.
Pros
Price guaranteed: you know exactly what you'll pay (or receive). No nasty surprises on illiquid stocks. Can optimise your entry by sitting slightly below the market and waiting for a pull-back.
Cons
- No fill guarantee: if the market never touches your price, your order sits idle.
- Can miss an opportunity on a stock that rallies without looking back.
When to use it
On an illiquid stock with a wide spread. When you want to catch intraday volatility: park an order slightly below market and let it work. For large quantities where a market order would move the price. To plan ahead an order ("buy if it dips to X MAD") without watching the screen.
Decision table
| Situation | Recommended type |
|---|---|
| Small order, very liquid stock | Market |
| Large order (>1 day's volume) | Limit, split if possible |
| Illiquid stock, spread > 1% | Limit, mid-spread |
| Need to exit now | Market |
| Waiting for a dip | Limit (below current price) |
| Waiting for a breakout | Market (or limit slightly above) |
Time in force
Once the order type is chosen, you also pick how long it stays alive:
Day: expires at market close. The most common default. Good Till Canceled (GTC): stays alive until filled or manually cancelled. Handy for long-term conditional orders ("buy if IAM dips below 90 MAD"). Good Till Date (GTD): stays alive until a date you choose. A middle ground between Day and GTC.
Tip: a poorly-managed GTC can fill weeks later in a totally different market context. If you use GTC, review your pending orders at least once a week.
Classic mistakes to avoid
1. Market order on an illiquid stock
On a small cap your order can move the price by several percent. Always prefer a limit order.
2. Limit too tight on the buy side
A limit 1-2 MAD below the best ask on a rallying stock often means you never fill. If you really want the stock, get to the front of the queue (at the best ask).
3. Forgetting GTC orders
A GTC sitting for months can fill in completely different market conditions. Do a weekly review.
4. Confusing limit with stop
A limit order fills at your price or better. A stop order triggers a market order when a threshold is hit — often used as a protection (stop-loss). Two different mechanisms.
Going further
The order book explained. How to invest on the Casablanca Stock Exchange. Brokerage fees on the Casablanca exchange. Full financial glossary