Expense ratio explained: Why even a small difference matters

Key takeaways:

• An expense ratio is the annual fee a mutual fund or ETF charges to cover operating costs, expressed as a percentage of the fund’s average net assets.
• Expense ratios are usually deducted through the fund’s net asset value, so they may not appear as a separate bill but still reduce net returns over time.
• Expense ratios vary by fund category, with actively managed mutual funds often costing more than broad passive ETFs, while sector-specific or niche funds may also carry higher fees.
• Assessing whether an expense ratio is competitive means comparing similar funds by category, strategy, risk, performance after fees and any additional charges.
• Even small expense ratio differences can compound over long periods, leaving more or less of a fund’s gross return available to the investor depending on costs and assumptions.

Investment costs can affect long-term returns, but not all costs are obvious at first glance. Expense ratios, which may look like a small percentage, reduce the fund returns investors receive after costs.

Knowing how expense ratios work can support comparisons between similar funds, especially when reviewing costs alongside risk, strategy and performance after fees. Over time, even minor differences in these fees can compound and significantly affect your portfolio's performance.

What is an expense ratio?

An expense ratio represents the annual fee a mutual fund or ETF charges investors to cover operating costs. It is expressed as a percentage of the fund's average net assets. This seemingly small percentage can significantly impact your returns over time, making it useful to understand what it includes and how it is calculated.

The expense ratio encompasses various costs required to manage and operate the fund, including:

• Management fees. Compensation for portfolio managers overseeing the fund.
• Administrative costs. Accounting, recordkeeping, and other operational expenses.
• Legal and compliance fees. Costs related to regulatory adherence and fund governance.
• Marketing and distribution. For some funds, this includes distribution-related fees, such as 12b-1 fees in the US.

How expense ratios work

Expense ratios are automatically deducted from a fund's net asset value (NAV), covering operational costs without requiring separate charges.

These deductions are built into the daily NAV calculation, so the costs remain invisible to investors but reduce the fund’s net return over time. While seamless, this ongoing fee has a meaningful long-term impact on portfolio performance, depending on the size of the fee difference, return assumptions and holding period.

Funds may report two types of expense ratios:

1. Gross expense ratio. Includes all costs without accounting for fee waivers or reimbursements.
2. Net expense ratio. Accounts for any waivers or reimbursements, reflecting the actual costs paid by investors.

For example, a fund with a gross expense ratio of 1% but offering a fee waiver of 0.2% would report a net expense ratio of 0.8%.

How is the expense ratio calculated?

The expense ratio is determined using the following formula:

Expense ratio (%) = (Total operating expenses ÷ Total fund assets) × 100

For example, if a fund's operating expenses amount to USD 50,000 and the total assets in the fund are USD 10,000,000, the expense ratio would be:

(USD 50,000 ÷ USD 10,000,000) × 100 = 0.5%

A 0.5% expense ratio would represent about USD 50 per year for every USD 10,000 invested, assuming the investment value stayed constant.

Example:

Let's say you invest USD 20,000 in an ETF with a 0.3% expense ratio. Over the course of a year, you would pay:

USD 20,000 × 0.003 = USD 60

This cost is reflected in the fund’s net asset value rather than usually appearing as a separate bill.

It's vital to understand the expense to assess a fund's cost-effectiveness and compare it to other investment options. Even slight differences in these fees can add up significantly over time.

Types of expense ratios across fund categories

Expense ratios vary based on the type of fund, reflecting differences in management approach, investment strategies, and operational requirements.

Mutual funds

Actively managed mutual funds typically have higher expense ratios. These costs arise from professional managers who analyse data, research opportunities, and adjust portfolios with the aim of outperforming market benchmarks.

As a result, expense ratios for mutual funds can vary widely and are often higher for actively managed funds than for broad passive funds.

Exchange-Traded Funds (ETFs)

ETFs generally have lower expense ratios, with most adopting a passive management approach. Designed to track an index such as the S&P 500 or MSCI Emerging Markets Index, ETFs incur fewer management costs. Expense ratios for ETFs are often lower than those of actively managed mutual funds, although they vary by provider, market, asset class and strategy.

For example, a broad-market ETF charging 0.03% may offer relatively low-cost exposure compared with higher-fee alternatives, although investors should also consider tracking error, liquidity, currency exposure and product structure.

Sector-specific or niche funds

Funds focused on specific sectors or themes, such as technology, renewable energy, or emerging markets, can often have higher expense ratios. The added complexity of managing these funds involves specialised research and unique market risks.

Expense ratios for these funds may range from 0.5% to 1.5% for actively managed options and from 0.1% to 0.5% for passive sector ETFs.