Buffer ETFs and Defined Return Autocallable ETFs both give investors a way to change the returns they receive from equity markets, but their approaches and roles within a portfolio differ.

Buffer ETFs typically offer participation in equity market appreciation up to a specified cap, while absorbing an initial portion of losses over an outcome period, usually one year. Investors bear losses beyond the buffer, while gains are limited to the cap even if the market rises further. Buffer ETFs, therefore, generally require markets to rise over the outcome period for a positive return to be generated.

Autocallables offer a predefined return if the underlying market meets specified conditions on observation dates, allowing returns to be generated when markets rise or remain flat and, in defensive implementations, even when markets fall moderately. They generally have a longer potential term, often six years, although they can mature early if conditions are met, hence the name autocallable. The capital barrier is generally assessed only at final maturity, giving markets time to recover from interim declines if equity performance is poor in the short term.

Alongside the maximum term, another meaningful difference between the strategies is the level and form of downside protection: a buffer absorbs the first portion of a market decline, while an autocallable may use a capital barrier that allows for a larger fall before capital repayment is affected. However, if the market finishes below that autocallable capital barrier, investors are exposed to the full decline from the initial index level.

How effectively do these strategies harvest risk premiums?

Both strategies take advantage of the equity, volatility, and skew risk premiums, although to different extents because of how their payoffs are constructed.

The equity risk premium is the additional return investors expect above risk-free rates for accepting equity market risk. Buffers generally assess outcomes over one year, whereas autocallables often have longer maximum terms, commonly six years. This can give markets more time to recover from interim declines in the short term, allowing longer-term equity growth and recovery to support the autocallable investment’s outcome.

Figure 1: Historical frequency of global equity declines

Source: WisdomTree, Bloomberg. Calculations using MSCI World Index (MXWO Index), USD price-return data. 31 December 1969 to 30 September 2026. Overlapping rolling returns calculated at monthly intervals. Historical performance is not an indication of future performance and any investments may go down in value.

Figure 1 uses the full available history of the MSCI World Index, spanning more than 50 years. Over this period, global equities fell by 15% or more in 9.1% of one-year periods, reaching or exceeding the protection provided by a 15% buffer, while no declines of that magnitude were observed over six-year periods. An autocallable with a final return barrier 25% below its initial index level could deliver its predefined return even if markets performed worse than any six-year outcome in the historical sample. A capital barrier 35% below the initial level would provide further room for declines before capital repayment was affected. The findings help to illustrate why prolonged exposure to the equity risk premium and an autocallable’s longer potential term may lead to improved outcomes.

The volatility risk premium reflects the difference between the volatility priced into options (implied volatility) and the volatility markets subsequently experience (realised volatility). Historically, implied volatility has on average exceeded realised volatility, providing compensation to option sellers, although during periods of market stress, realised volatility can exceed what was priced in and lead to substantial losses.

Harvesting the volatility risk premium is akin to selling insurance, where premiums are generally set above expected claims to compensate the insurer for accepting risk. Both autocallables and buffers sell downside protection to the market, but they have different upside profiles to provide their respective returns. In a buffer, the investment participates in equity market appreciation up to a predefined cap. This upside participation offsets part of the short-volatility exposure from a buffer’s downside exposure. An autocallable’s predefined return does not generally require market appreciation, and its payoff construction typically results in greater net short-volatility exposure at inception. Autocallables, therefore, tend to have more exposure to the volatility risk premium as a potential source of return.

Autocallables can also benefit from greater volatility skew, where protection against larger declines tends to command higher implied volatility. A buffer might absorb the first 15% of a market decline, while an autocallable might repay capital in full provided the index finishes no more than 35% below its initial level at maturity. If it finishes below that barrier, however, investors are exposed to the full decline from the initial index level. This barrier structure allows autocallables to monetise the relatively expensive protection against deeper declines differently from buffers, generally enhancing potential returns through a skew risk premium.

Considering the strategies in multi-asset portfolios

For investors who expect equity markets to perform reasonably well over the coming year, buffer ETFs may be a useful way to participate in that growth while absorbing an initial portion of any decline. Positive returns remain dependent on market appreciation, but the buffer can make it more comfortable for investors to retain equity exposure when they are also concerned about moderate potential losses.

Autocallables offer a different return profile within a portfolio, with predefined returns often in the region of 6% to 10% per annum, achievable in flat or, depending on the structure, moderately falling markets. This can complement investments that require appreciation to perform well, offering scope to generate returns comparable to those of equities over the long term and to outperform when markets make limited progress. However, returns are capped at the predefined level, and investors remain exposed to the full decline in the underlying market if capital repayment conditions are not met.

Both buffers and autocallables can be implemented as diversified, laddered portfolios, spreading investments across starting dates and maturities to help reduce reliance on a single market entry point. However, the generally longer potential term of autocallables can allow for additional diversification through a wider spread of entry points over time.

Actively managed portfolios of autocallables can diversify exposure across underlying equity indices, capital barriers, maturities and counterparties. Through exposure to equity, volatility and skew risk premia, the Defined Return Autocallable strategies aim to increase the likelihood of achieving their target returns across a wider range of equity market conditions. These funds and ETFs can therefore provide a source of diversification that supports portfolio returns without necessarily relying on sustained equity market appreciation.

For Illustrative purposes only. Actual caps, buffers, predefined returns, barriers and maturities vary by strategy and structure.