Synthetic ETF — How does it differ from physical ETF?

What is a synthetic ETF?

A synthetic ETF is an index fund that doesn't directly buy stocks or bonds that make up the index. Instead, it uses swap contracts with an investment bank (counterparty) to replicate the index performance.

Quick Answer

A synthetic ETF is an index fund that does not directly buy the index's stocks or bonds, instead holding a collateral basket and entering a swap contract with an investment bank that pays the exact index return. This delivers lower tracking error and access to hard-to-reach markets (e.g. CSI 300), but introduces counterparty risk — if the bank defaults. UCITS rules cap swap exposure at 10% of fund assets and most providers use overcollateralization, yet the risk is not zero. For mainstream indices a physical ETF is usually safer. This is educational information, not investment advice.

---

How does physical replication work?

A physical ETF buys all (or most) securities from the index. If you're tracking the S&P 500, the fund buys 500 stocks in appropriate proportions.

Advantages: Simplicity, no counterparty risk. Disadvantages: Higher transaction costs (especially for large indices), tracking error from rebalancing costs.

How does synthetic replication work?

A synthetic ETF holds a collateral basket — often other stocks or bonds — and enters a swap contract with a bank. The bank commits to pay the fund the exact index return in exchange for the return from the collateral basket.

ETF ← swap → Investment bank
ETF provides: return from collateral basket
Bank provides: return from target index

Counterparty risk

The main concern with synthetic ETFs: What if the counterparty bank goes bankrupt? In practice:

• UCITS regulations limit swap exposure to 10% of fund assets.
• Most synthetic ETFs use overcollateralization — collateral exceeds 100% of value.
• Large banks (Goldman Sachs, Deutsche Bank) rarely go bankrupt, but the risk exists.

When is a synthetic ETF better?

• Hard-to-access markets — E.g., Chinese indices (CSI 300), where direct stock purchases are restricted.
• Lower tracking error — Swap guarantees exact index return.
• Tax efficiency — In some jurisdictions, synthetic ETFs avoid withholding tax on dividends.

Examples

Which to choose?

For most retail investors, a physical ETF is the safer and simpler choice. Consider a synthetic ETF when you want access to an exotic market or minimal tracking error is crucial.

How Freenance can help?

Freenance tracks both types of ETFs in your portfolio. You see composition, costs, and performance regardless of replication method — all in one dashboard.

👉 Track your ETFs with Freenance — freenance.io

Related Articles

• Jak sprawdzić opłaty w funduszu inwestycyjnym — ukryte koszty, TER, opłaty manipulacyjne
• Co to jest portfel Bogleheads — filozofia i 3-fund portfolio po polsku

FAQ

Is a synthetic ETF safe under UCITS rules?

Synthetic ETFs sold in the EU operate under the UCITS framework, which caps swap counterparty exposure at 10% of fund net assets. Most providers also post collateral above 100% of swap value to further reduce risk. The structure is regulated, but counterparty exposure is not zero.

What happens if the swap counterparty defaults?

If the investment bank on the other side of the swap fails, the ETF still holds its collateral basket, which can be liquidated to cover the loss. The residual gap is typically limited by overcollateralization and the UCITS 10% cap, but a fast-moving default could still produce a small tracking shortfall. This is a market and counterparty risk, not a guarantee of full recovery.

Why do some synthetic ETFs have lower tracking error than physical ones?

A swap contract pays the ETF the exact index return net of fees, so the fund does not have to rebalance hundreds of underlying securities. This avoids drag from spreads, taxes on internal trades, and small index changes. For very broad or hard-to-access indices, this can mean meaningfully tighter tracking.

Are synthetic ETFs more tax-efficient on US dividends?

In some structures, a synthetic ETF can receive index-equivalent returns through a swap without the underlying dividend being subject to the same withholding tax that a physically replicated fund would pay. The benefit depends on the fund domicile, the index, and current tax treaties. Confirm the prospectus and KID before assuming any tax advantage.

Should a long-term retail investor in Poland pick synthetic or physical?

For mainstream indices like MSCI World or S&P 500, a physical ETF is usually simpler, transparent, and good enough. Synthetic replication can make sense for niche markets (e.g. China A-shares) or when minimizing tracking error matters more than counterparty exposure. This is general information, not investment advice — your decision should match your own risk tolerance and goals.