iShares S&P 500 Swap ETF aims to replicate the S&P 500’s net total return mainly by using unfunded total return swaps that reference the S&P 500; to meet those swap payments the fund holds a basket of equity securities from global developed markets whose returns are passed to swap counterparties. If swaps aren’t possible, the ETF can use other derivatives (for example options or non‑deliverable futures), invest in other funds, or directly hold shares that, as far as practicable, match the S&P 500’s component stocks. The S&P 500 itself is a free‑float, market‑capitalisation weighted index of the 500 largest U.S. companies across leading industries.