👉 Exchangeability is a property of financial markets that refers to the fact that all trading activities in these markets are performed at the same time, regardless of whether or not they involve different parties. This means that if one trader buys and sells a security at an agreed-upon price, it cannot be said that the other party has bought and sold the same security at another agreed-upon price. Instead, both traders have executed their trades at the same time, resulting in no transaction costs or delay between them