The Quality Veto

Everything so far has been about fit — matching delta to the move and DTE to the timing. Fit is necessary. It is not sufficient.

A contract can sit in exactly the right cell of the matrix and still be a contract you should refuse, because the price you actually transact at is not the price you analysed.

What you actually pay

Every quoted option has two prices. You buy at the ask and sell at the bid. The mid-price in the middle is a convenient fiction — nobody transacts there.

The gap between them is paid twice: once entering, once exiting. It is not a fee you notice on a statement. It is subtracted from your result before any of the analysis in this course gets a chance to matter.

Here is what that costs across the real chains used in this course.

A 10 percent spread means the stock must move enough to earn 10 percent before you break even — and then earn your actual profit on top. On a trade targeting a 20 percent return, half of it is gone to the spread before you start.

Liquidity differs more than you expect

Notice the pattern in that table. SPY's out-of-the-money calls quote one or two cents wide. GOOGL's quote ten to fifteen cents on a similar premium.

SPY is one of the most liquid options markets in the world, with daily expiries and one-dollar strikes. GOOGL is liquid by most standards and still quotes ten times wider in percentage terms at the same part of the chain.

This has a direct consequence for the matrix: the same cell is not equally available on every underlying. A delta-0.15 contract at 8 DTE is a reasonable expansion trade on SPY and a considerably worse one on GOOGL, purely because of what it costs to get in and out.

Reading spread correctly

One trap worth naming, because it catches careful people. Percentage spread on its own is misleading at both ends of the chain.

On a cheap contract, percentage exaggerates. The GOOGL 1DTE 340 call quotes 0.38 by 0.45 — that is 17 percent, which sounds alarming, but the spread is seven cents. With a one-cent tick and a 42-cent premium, that is a normal market, not a broken one.

On an expensive contract, percentage understates. A contract quoting 34.77 by 38.64 is only about 10 percent wide, but the spread is $3.87 — nearly four dollars of round-trip cost.

The rule that handles both ends:

Acceptable spread ≤ max($0.10, 10% of mid)

The dollar floor protects cheap contracts from a percentage test that punishes them for having a small denominator. The percentage governs expensive contracts, where a small-sounding percentage hides a large absolute cost.

Implied volatility — are you paying a fair rate?

The third quality term is whether the contract is expensive in volatility terms, independent of its dollar price.

Implied volatility is the rate the market charges for uncertainty. A contract with unusually high IV relative to its own history is expensive even if the premium looks small, and it carries an extra way to lose: if IV falls after you buy, the contract loses value even when price moves your way.

On the GOOGL eight-day chain, IV runs about 29 to 32 percent across the ladder — a gentle smile, slightly higher at the wings. That consistency is what a healthy chain looks like. A strike quoting far outside its neighbours' range is usually a quoting artifact rather than an opportunity.

The full quality score

Put all of it together and fit becomes one term among several:

ContractQuality = DeltaFit + DTEFit + Liquidity + TightSpread + ReasonableIV

The important property of this formula is that the later terms can veto the earlier ones. A contract at delta 0.65 and 10 DTE — the safest cell on the board — is still a reject if its spread is a quarter of its premium.

That is not a rounding adjustment to a good trade. It is a different trade, one where you start a quarter of the way down and have to climb out before the thesis even begins to pay.

The discipline

Before buying, three checks that take about ten seconds:

1. Spread — is it within max($0.10, 10% of mid)? If not, look for a nearer strike or a more liquid expiry.
2. Open interest and volume — is anyone else trading this contract? A strike nobody holds will be difficult to exit at a fair price regardless of the quoted spread.
3. IV sanity — is this strike's implied volatility in line with its neighbours?

Fail any one, and move. There is almost always an adjacent contract with nearly the same delta and a far better book — and giving up 0.03 of delta to halve your transaction cost is an easy trade to make.