Put-Call Parity, the hidden link between every call and put

A 3 minute 38 second animated lesson on put-call parity, the no-arbitrage relationship that ties European calls and puts on the same stock to the spot price and a bond. Built for students of financial markets and derivatives, and useful for anyone meeting option pricing for the first time.

The video builds two portfolios that look different but pay exactly the same at expiry. A call plus a bond worth the strike, and a put plus one share, both deliver the larger of the stock price and the strike. Because the payoffs are identical in every scenario, the law of one price forces the two portfolios to the same cost today, which is the parity equation C + K e^(-rT) = P + S0. When the relation breaks, the fix is mechanical: sell the overpriced side, buy the underpriced side, and the payoffs cancel at expiry for a riskless profit, so arbitrageurs close the gap fast.

The lesson closes on the idea worth keeping. Fix any three of the four prices and the fourth is pinned, because two ways to build one payoff must cost the same. The equality holds for European options only. American options give an inequality, and dividends shift the spot term down. Pair the video with the Atlas concept page for the full derivation, a quick quiz, and citations to Hull (2022), Stoll (1969), and Merton (1973).