Premium seller (P7) · 10 units
The mechanics of selling premium
Selling premium is a mechanics discipline before it is anything else. This path starts with the option contract itself, then theta, then the structures premium sellers actually use — covered calls, cash-secured puts, condors — described by their risk shape, not endorsed. Generic instruments throughout; each unit ends on a command you can run.
Start the pathCalls and puts, rights and obligations- Options · BeginnerCalls and puts, rights and obligationsAn option is a contract, not a share. A call gives its buyer the right — never the duty — to buy 100 shares of an underlying at a fixed strike price, with a fixed expiry as the deadline; a put gives the right to sell at the strike. The buyer pays a premium up front for that right and can walk away; the most they lose is the premium. On the other side, the writer collects the premium and takes the obligation: if the buyer exercises, the writer must deliver. That asymmetry — a right on one side, an obligation on the other — is why optionality has a price at all. This unit defines the call and the put, separates the buyer from the writer, and reads a generic contract as what it is: a priced choice about the future, settled on a deadline you agree to at the start.
- Options · BeginnerMoneyness and the clockMoneyness describes where the strike sits relative to the current price. A call is in-the-money (ITM) when price is above the strike, at-the-money (ATM) when they are level, and out-of-the-money (OTM) when price is below; for a put the directions flip. Moneyness is not fixed — it moves every time the underlying moves, so an OTM call becomes ATM then ITM as price rises past its strike. Expiry is the contract's deadline: the date after which the right simply ends. Picking a strike and an expiry is a statement about how far you think price could travel and by when. This unit places three strikes around a generic price, shows how each one's moneyness changes as price moves, and frames the clock as the second axis every option is priced on alongside the strike.
- Options · BeginnerWhy you pay what you payAn option's premium splits into two parts. Intrinsic value is the amount the option is already in-the-money — a $100 call with price at $106 holds $6 of intrinsic value, and never less than zero. Extrinsic value, often called time value, is everything above intrinsic: what you pay for the chance that price moves further your way before expiry. An out-of-the-money option has zero intrinsic value, so its entire premium is extrinsic — you are buying time and volatility, nothing you could exercise today. Extrinsic value is largest when there is more time left and when the market expects bigger moves, and it decays toward zero as expiry approaches. This unit takes one premium apart into its intrinsic and extrinsic halves on a generic contract, so a price stops being a single number and becomes two questions with two different answers.
- Options · BeginnerWhat happens at the endExercise is the option buyer invoking their right — a call buyer buying at the strike, a put buyer selling at it. Assignment is the mirror on the writer's side: when a buyer exercises, the clearing house assigns a writer who must deliver. Settlement is how the delivery happens. Physically-settled options hand over the actual shares at the strike; cash-settled options (common on index contracts) just pay the in-the-money difference in cash. Most in-the-money options are handled automatically at expiry, and out-of-the-money ones simply expire worthless. Pin risk is the edge case: when price finishes almost exactly at the strike, whether an option lands in- or out-of-the-money — and so whether it is assigned — can flip on the last prints. This unit walks one generic contract through expiry so the ending stops being a mystery.
- Options · BeginnerReading the chainAn option chain is the full grid of contracts on one underlying: every strike, down the rows, for each expiry, with calls usually on one side and puts on the other. Each cell carries the same handful of columns. Strike and expiry identify the contract. Bid and ask are the two live prices — the bid is the highest price a buyer will pay, the ask the lowest a seller will accept — and the gap between them is the spread you cross to trade. Volume is how many contracts changed hands today; open interest is how many contracts exist and remain open. Implied volatility is the market's expected movement, backed out of the premium. Read together, the chain is a map of where the market has parked its attention and its opinions. This unit reads one generic chain column by column so the grid stops being noise.
- Options · IntermediateTheta: the price of timeTheta is how much an option's value decays with the passage of one day, all else held equal. It acts on extrinsic value — the time-and-chance portion of the premium — draining it toward zero as expiry approaches. Theta is negative for the option buyer, who watches value bleed away each day the underlying sits still, and positive for the writer, who collects that decay. The decay is not linear: it accelerates as expiry nears, so an at-the-money option loses time value fastest in its final days. Weekends still count — three days of decay are priced in even though markets are shut for two of them. This unit reads theta on the same generic at-the-money call from the delta and gamma units, framing time value as rent the buyer pays and the writer collects, with no claim about which side wins.
- Options · IntermediateOne position, all four greeksThe greeks are one dashboard, not four separate facts. On any single option they read together: delta is directional exposure, gamma is how fast that exposure changes, theta is what each day costs, and vega is exposure to changes in implied volatility. Reading them at once is the actual skill, because they pull against each other — a long option that carries positive gamma (it gets more directional as it moves your way) also carries negative theta (it bleeds value every quiet day), and the same contract's vega means an IV drop can hurt even when direction helps. This capstone takes the one generic at-the-money call carried through the delta, gamma, theta, and vega units and reads all four numbers on it simultaneously across a few scenarios, so the greeks stop being trivia and become a single instrument panel you scan before and during a position.
- Options · AdvancedThe mechanics of selling premiumSelling premium means taking the other side of an option: you collect its price up front and take on the obligation the buyer paid for. Three common structures share that mechanic. A covered call sells a call against stock you already own, so the shares stand behind the obligation. A cash-secured put sells a put with cash set aside to buy the stock if assigned. The wheel simply alternates the two. In every case the payoff is inverted from a buyer's: bounded gain — the premium collected, plus any capped move in the stock — set against a much larger obligation on the other side. Time is the seller's tailwind, since theta works for the position, while a sharp move against it is the exposure. This unit lays out the mechanics and the risk shape of each structure on a generic instrument — what the seller is obligated to, and where the exposure sits — not whether to sell, and not that it works.
- Options · AdvancedCondors and flies: trading a rangeAn iron condor and an iron butterfly are range structures built by combining verticals. Stack two opposing vertical spreads — one above the current price and one below — and the position profits inside a band while its risk stays defined outside it. A condor keeps its two inner strikes apart, so the profitable zone is a wide plateau, the tent; an iron butterfly pushes those inner strikes together to a single point, so the tent narrows to a peak. In both, the outer strikes are the edges of the tent: beyond them, loss is capped and known. The structure expresses a view about where price will stay, not which direction it will go, and every leg's maximum loss and gain are fixed at entry. This unit assembles a condor and a fly on a generic instrument, showing where the edges of the tent sit and why the two shapes are the same idea at different widths.
- Kestrel-native · IntermediateThe receipt you can re-verify yourselfA proof URL is a certified Grade served as a public, anonymous, read-only artifact — no account, no key, no login. Two independent checks make it trustworthy without trusting the server. In a browser, the page fetches kestrel's published verify key from a well-known document and re-verifies the Grade's Ed25519 signature client-side, against the artifact's pinned roots. On the command line, the CLI goes further and recomputes the whole record byte for byte on your own machine, then asserts it matches. Either way you trust the math, not the server's word for it. That is why a proof URL is the conversion evidence an agent hands its human at the end of a free trial: it is a shareable, re-verifiable object, not a screenshot or a claim. This unit explains what a proof URL contains, the two checks anyone can run, and why the receipt is the atom the whole trust chain is built from.