Advanced ETFs

An exchange-traded fund (ETF) aims to replicate the return of a reference index. There are two broad replication METHODS, and the method drives the fund's risk profile.

• •PHYSICAL replication: the ETF actually BUYS the underlying securities. It may hold every constituent (full replication) or a representative subset (sampling / optimised replication) when the index is very large or illiquid.
• •SYNTHETIC replication: the ETF does NOT hold most of the index constituents. Instead it enters a total return SWAP with a counterparty (usually a bank) that agrees to PAY the ETF the index return, in exchange for a fee and the return on a separate basket of assets the ETF holds.

Physical funds carry the operational reality of holding and rebalancing many securities; synthetic funds substitute that for a contractual promise from a swap counterparty. Understanding which method a fund uses is essential to understanding its risks.

In a synthetic ETF the index return is delivered through a total return SWAP. Because the return depends on the counterparty honouring the swap, the fund is exposed to COUNTERPARTY (default) RISK: if the swap counterparty fails, the ETF may not receive the promised index return.

To contain this, synthetic structures use COLLATERAL. The counterparty posts collateral (a basket of securities or cash) that the ETF can claim if the counterparty defaults. Two common structures:

• •UNFUNDED swap: the ETF uses investors' cash to buy a substitute basket of securities and swaps that basket's return for the index return.
• •FUNDED swap: the ETF passes cash to the counterparty and receives the index return, with collateral posted (often into a segregated account) to secure the exposure.

The residual risk is measured by the SWAP EXPOSURE (net counterparty exposure) — how far the value the counterparty owes the ETF exceeds the collateral held. Regulators typically cap single-counterparty exposure and require the collateral to be marked-to-market and of adequate quality. Key collateral risks: the collateral may be of LOWER quality or different from the index, and in a stressed market it may be hard to sell at its marked value (collateral/liquidity risk).