Bid, Ask, and Mid: How Option Prices Work in Practice

Open any options chain and you'll see two prices side by side: the bid and the ask. They're never the same number, and the gap between them is the first thing to understand before placing a covered call order.

The bid is what buyers are willing to pay. The ask is what sellers are asking for. When you sell a covered call, you're the seller — you'd like to receive as close to the ask as possible. When you buy back a covered call to close the position early, you're the buyer — you'd like to pay as close to the bid as possible.

In practice, the realistic target for both transactions is the midpoint between bid and ask — called the mid or the mark.

What Bid, Ask, and Mid Look Like in Practice

Suppose you're selling the MSFT $440 call expiring in 30 days. The options chain shows:

• Bid: $3.20 — the highest price any buyer is currently willing to pay
• Ask: $3.65 — the lowest price any seller is currently willing to accept
• Mid: $3.42 — the midpoint between the two

If you place a market order to sell this option, your brokerage sells it at the bid — $3.20. You give up $0.22 per share ($22 per contract) for the convenience of an instant fill. For one contract that's modest; across a portfolio of five to ten positions per year, it accumulates to several hundred dollars in unnecessary friction.

If you place a limit order at the mid ($3.42), you might fill there, or slightly below if the market shifts before your order executes. You'll sometimes wait a few minutes. But $22 per contract recovered is real income.

Always use limit orders. Never place a market order on an option. Option liquidity is thinner than stock liquidity. A market order on a less active option can fill at the ask or worse. Limit orders are the difference between trading like a professional and trading like someone in a hurry.

What the Spread Tells You About Liquidity

The gap between bid and ask — the spread — reflects how actively traded the option is and how confidently market makers can price it.

A tight spread (bid $3.35, ask $3.45, spread $0.10) means high liquidity: lots of participants, confident market makers, minimal friction getting in and out.

A wide spread (bid $2.80, ask $3.60, spread $0.80) means low liquidity: fewer participants, higher uncertainty in the pricing, and meaningful friction on every transaction.

The engine filters out options where the bid-ask spread exceeds 10% of the mid price. Here's how to calculate it yourself:

Spread % = (Ask − Bid) ÷ Mid × 100

• Bid $3.20, Ask $3.65, Mid $3.42: spread = $0.45, spread % = 13.2% — fails the filter
• Bid $3.35, Ask $3.45, Mid $3.40: spread = $0.10, spread % = 2.9% — passes comfortably

In practice, large-cap stocks with actively traded options — AAPL, MSFT, NVDA, JPM — typically show spreads well under 10%. The filter protects you from trades where the spread would eat too much of the premium you're trying to collect. An option showing a $4.00 premium with a $0.70 spread is a less attractive trade than it appears: just crossing the spread costs you nearly 18% of your income before the first day of theta decay.

How to Place the Order

The practical sequence for opening a covered call position:

1. Pull up the options chain and find the strike matching your strategy level. Note the bid, ask, and mid before touching anything.

2. Set up a "sell to open" limit order at the mid price. Round to the nearest $0.05 if your brokerage requires it ($3.42 → $3.40 or $3.45).

3. Set the order duration to "day" — good for today only. You don't want an open order sitting overnight ready to fill at a stale price the next morning.

4. Submit and watch. For liquid options, fills at or near the mid typically happen within a few minutes during market hours. If you're trading at the open (first 15 minutes) or close (last 15 minutes), spreads are often wider — mid-day execution is usually smoother.

5. If not filled in 10-15 minutes, consider moving your limit down $0.05 toward the bid. The mid is a target, not a right. Sometimes the market simply won't fill at mid, and a small concession gets you done.

The same logic applies in reverse when closing a position early. A "buy to close" limit order at the mid gets you out at fair value rather than gifting the spread to market makers.

The Mid Isn't Always Fair Value

The mid is a starting point, not an oracle. Market makers set bids and asks based on their own inventory and risk exposure — the midpoint between two numbers they control can drift from what buyers are actually willing to pay.

For large-cap stocks with heavy options volume, the mid is usually close to fair value and fills are common. For lower-volume names, far out-of-the-money strikes, or unusual expirations, the mid can overstate what the market will pay. If you've been sitting at the mid for 20 minutes with no fill and the stock hasn't moved, the market is probably telling you the option isn't worth mid. Adjust toward the bid in $0.05 increments.

One useful sanity check: look at the last trade price (sometimes labeled "last" on the chain). If the last trade printed at $3.30 and you're trying to sell at $3.42, you're above where the market recently transacted. That's not necessarily wrong — markets move — but it's useful context.

Closing Early: The Bid-Ask Math on Exit

The spread on the closing transaction matters as much as on the opening one, but the stakes are different. When you're closing a position that's decayed from $3.42 to $1.70, the option chain might show:

• Bid: $1.62
• Ask: $1.78
• Mid: $1.70

Your "buy to close" limit order at $1.70 (the mid) is your target. Spread = $0.16, spread % = $0.16 ÷ $1.70 = 9.4% — just inside the 10% threshold but worth noting. If you're in a hurry to close, paying $1.78 (the ask) costs you an extra $0.08 per share ($8 per contract) relative to filling at mid.

On a 100-share position opened at $3.42 and closed at mid for $1.70, your profit is $172 per contract. Opening at the bid ($3.20) and closing at the ask ($1.78) instead would have netted $142 — a $30 difference on one contract purely from order placement. Across a year of trading, sloppy execution is a meaningful drag on returns.

(For the context on why you might close at 50% profit in the first place, see Should You Close Your Covered Call at 50% Profit?. For how the floor price determines whether the trade is worth doing at all, see The Number That Decides Whether a Trade Is Worth Taking.)

Frequently Asked Questions

What if my brokerage shows a different mid than the app suggests?

Options prices update in real time. The mid displayed by the app reflects the chain at the moment the recommendation was generated. By the time you open your brokerage, a few minutes may have passed and the chain may have shifted. This is normal — use your brokerage's live quote as the actual reference point for your order, treating the app's recommendation as the target strike and strategy guidance.

Should I always aim for the mid, or sometimes try to do better?

You can try for better than mid — place your limit above mid and see if the market comes to you. In practice, large-cap options during normal market hours typically fill at mid or close to it. Trying for above mid often means waiting or not filling, which can cost you a day of theta decay. The mid is a practical target because it splits the spread fairly.

What does it mean if the bid is $0.00 on a far out-of-the-money option?

A $0.00 bid means no buyers are currently willing to pay anything for that option. The ask might still show a value (market makers are willing to sell it, but only for their price), but you can't sell an option if no one will pay you for it. This typically affects deep out-of-the-money options near expiration. You'll never encounter this situation in covered call recommendations because the floor price filter eliminates options with premiums too thin to trade.

Is the bid-ask spread always quoted in the options chain?

Yes — any options chain will show bid and ask. The mid (sometimes labeled "mark") may or may not be displayed by default depending on your brokerage. If you don't see it, calculate it: (bid + ask) ÷ 2. You can usually add the "mark" column to your options chain view in most brokerages' settings.

Does the spread widen during volatile market periods?

Yes. When implied volatility spikes — during market selloffs, earnings surprises, or macro events — bid-ask spreads often widen as market makers protect themselves against rapid price changes. A stock that normally shows a $0.10 spread might show $0.30-$0.50 during a volatile session. This is one reason the engine's 10% spread filter exists: in volatile periods, some options that would normally clear the filter fail it because their spreads have widened, and a Skip is the correct outcome.