Order types that protect you

The price on your screen is not a promise. Your order type shapes what you pay and where you get out.

Bid and ask

The bid is the highest price a buyer offers right now. The ask is the lowest price a seller will take. The gap is the spread. Buy at market and you usually pay the ask. Sell at market and you usually get the bid.

The orders

Market. Fills now at the best available price. The price is not guaranteed, especially in a fast move or a thinly traded stock.

Limit. You set the worst price you accept. A buy limit at $50 fills at $50 or lower. If price never gets there, nothing happens.

Stop (stop-market). Turns into a market order once the stock trades at or through your stop price. Own a stock at $100 with a sell stop at $95, and a trade at $95 or lower sells your shares at the next available price, which can be below $95.

Stop-limit. Same trigger, but it becomes a limit order. Stop $95, limit $94 means sell, but not below $94. If the stock drops straight through $94, you may not sell at all.

Trailing stop. A sell stop that follows price up and never moves down. Buy at $100 with a 5% trail and the stop starts at $95. If the stock climbs to $120, the stop rises to $114.

Bracket and OCO. A bracket attaches a profit target and a stop to your entry. When one of the two exits fills, the other is canceled, which is what one-cancels-other (OCO) means.

The gap problem

A stop triggers when the stock trades at or through your price. If bad news comes after the 4:00 PM ET close and the stock opens at $88, a $95 stop sells near $88. The stop-limit from above ($95 stop, $94 limit) does not sell unless the stock climbs back to $94. Keeping each position small is the simplest way to limit this risk. Trading can lose money, sometimes more than your stop suggests.

Day vs good-til-canceled

A day order expires if unfilled at the end of the regular session, 9:30 AM to 4:00 PM ET. A good-til-canceled (GTC) order stays open until filled or canceled, though many brokers cancel it after a set period. Forgotten GTC orders can cause surprise fills. Outside regular hours, most brokers accept only limit orders, and a market order placed after the close usually waits for the next open.

Why limit orders matter on options

Say a contract shows bid $2.00, ask $2.40, so the midpoint is $2.20. A market buy usually fills at $2.40, or $240, since one contract covers 100 shares. Sell right away and you get the bid, $200. That is $40 gone, about 17% of what you paid, before fees and before the stock moves.

Instead, place a limit near the $2.20 midpoint. No fill after a minute or two? Move it a few cents toward the ask. When selling, start at the midpoint and move toward the bid. Some brokers do not allow stops on options at all.

Order	Benefit	Risk
Market	Almost always fills	Worse price than you saw
Limit	You control the price	May never fill
Stop	The exit happens	Gaps fill below the stop
Stop-limit	Price floor on exit	No fill in a fast drop
Trailing stop	Keeps part of a gain	Normal swings can trigger it
Bracket / OCO	Exits set in advance	Not at every broker

Order rules differ by broker. Options buyers can lose 100% of the premium paid.

Try this

In a paper trading account, pick a stock you follow and buy 10 practice shares. Set a 5% trailing stop on them and a separate buy limit 2% below today's price. Check daily for a week and note what filled. Then write down the bid and ask for three strikes on its option chain.