What is a Money Market Fund? A Comprehensive Guide to Risks and Benefits of Money Market Fund

Money market funds have recently become a focal point for smart capital management and short-term financial planning. Whether you are looking for a place to "park" idle cash, seeking flexible yield, or aiming for better returns than traditional fixed deposits, money market funds  are often regarded as a low-risk, high-liquidity choice. But is a money market fund truly "zero-risk"? And how does it stack up against a bank fixed deposit? At StashAway, we believe in being Open & Transparent. Here is everything you need to know about the advantages and risks of money market funds.

What exactly is a Money Market Fund?

A money market fund is a type of mutual fund that specifically invests in short-term, highly liquid, and low-risk financial instruments. These funds typically focus on assets with maturities of less than one year and high credit ratings, including:

• Short-term government bonds (e.g., US Treasuries)

• Bank certificates of deposit

• Commercial paper

• Repurchase agreements 

• High-credit-rated short-term corporate bonds

Who are Money Market Funds for?

Due to their high liquidity and low-risk profile, money market funds are ideal for investors who need their capital to remain accessible at a moment's notice. They allow conservative investors to enjoy yields that are typically higher than standard fixed deposits.

For investors weighing their next move, money market funds offer a strategic place to park idle cash. It’s an ideal liquidity management tool that allows you to earn competitive yields while keeping your capital ready for whenever the right opportunity arises.

The Strategic Advantages of Money Market Funds

One of the most compelling advantages of money market funds is their liquidity, offering far greater flexibility than traditional Fixed Deposits. Most money market funds operate on a T+1 redemption cycle—meaning your funds are available as soon as the next business day, while some platforms even offer same-day access. If you’re planning to enter the stock market next week, you can strategically park your idle cash in money market funds to earn yield in the meantime. When the right market opportunity arises, you can quickly redeem your capital, ensuring your wealth remains as agile as your investment strategy.

By investing primarily in short-term, secure assets such as government bonds and bank certificates of deposit, money market funds maintain exceptionally low default risk and volatility, making them a cornerstone of low-risk investing. Despite their conservative nature, they continue to offer compelling yields; in 2024, USD money market funds and HKD variants delivered returns generally exceeding 5% and 4% respectively¹, consistently outperforming most traditional bank fixed deposit rates.

Another compelling advantage of money market funds  is that interest is calculated daily. This means you can earn accrued interest even if you redeem your funds instantly, without having to wait for a maturity date. For instance, if you originally planned to hold your money market funds for three months but need to withdraw early due to an unexpected cash flow requirement, your earned interest will be automatically included in the payout. There are no penalty rates or withdrawal fees to worry about.

Understanding Money Market Fund Risks

While money market funds are highly secure, they are not "risk-free." As a sophisticated investor, it is vital to understand the potential trade-offs to build a resilient portfolio.

Market Volatility and Interest Rate Risks

To a certain extent, money market funds remain sensitive to market dynamics. When market interest rates rise, the value of existing bonds typically declines. Although money market funds primarily consist of short-term debt, extreme market conditions can still impact their net asset value. A clear example occurred in 2022, when the US Federal Reserve implemented three aggressive rate hikes totalling 2.25%. This led to heightened volatility across money market funds, putting pressure on both returns and pricing¹. In instances of extreme market stress, some funds even saw their NAV briefly dip below $1—a phenomenon known as 'breaking the buck'². This underscores that while money market funds are low-risk, they are not entirely immune to market fluctuations.

Currency Risk

When you invest in a money market fund denominated in a foreign currency, your returns are subject to exchange rate fluctuations.

Suppose you invest $100,000 HKD in a USD money market fund (at an exchange rate of 7.85) with an annualized return of 4%. If the USD depreciates by 5% to 7.41 during the holding period (note: this example does not account for the Hong Kong Linked Exchange Rate System), the actual return would be calculated as follows:

• Principal: $100,000 HKD = $12,820 USD
• Interest: $12,820 USD x 4% = $512 USD
• Total Amount: $13,332 USD x 7.41 = $98,790 HKD
• Total Loss: $1,210 HKD

As the example illustrates, fluctuations in foreign exchange rates directly impact the returns of non-local money market funds. We encourage investors to remain mindful of these currency dynamics when managing their portfolios.

Why Consider a USD Money Market Fund?

Since USD money market funds are directly driven by the US Federal Funds Rate, their annualized yields are generally higher than those of HKD equivalents¹. This makes them an ideal choice for investors looking to capture higher returns within a low-risk framework, provided they remain mindful of the currency risks mentioned above.

As the world’s primary reserve currency, the USD also offers stronger long-term inflation-hedging capabilities compared to other currencies. This is particularly strategic for money market fund investors who have existing USD obligations or a bullish outlook on the dollar’s trajectory. Its global dominance further enhances allocation flexibility, helping investors effectively diversify regional risks within their portfolios.

Money Market Fund vs Fixed Deposit

While both money market funds and bank fixed deposits are considered low-risk financial tools offering stable returns, there are strategic differences between the two in terms of flexibility, yield, and capital protection:

StashAway | Intelligent Wealth Management for a Stable Portfolio

Beyond money market funds , investors can leverage StashAway Cash Yield to manage cash with even greater precision.

With an annualized yield of 4.3% p.a. (as of 22 April 2025), our Cash Yield portfolio invests primarily in ultra-short-term US Treasuries. Much like a money market fund, there are no lock-ins, making it perfect for emergency funds or tactical cash management. Furthermore, as Asia’s leading investment platform, StashAway leverages Modern Portfolio Theory (MPT) alongside our proprietary ERAA® framework. By intelligently navigating ultra-short-term US Treasuries and other asset classes—including Equity ETFs, Bond ETFs, and Gold—we empower investors to build resilient, high-performance portfolios across all economic cycles, effectively diversifying risks across markets and assets.

Why Partner with StashAway?

• Asset Protection: Your assets are held by custodian banks (Citibank and HSBC), strictly segregated from our operational funds.

• Regulated & Trusted: We are licensed by the HK SFC (Types 1, 4, and 9) and regulated across Singapore, Malaysia, Thailand, and the UAE.

• Automated Intelligence: Our ERAA® framework automatically adjusts your portfolio based on your unique risk appetite and the changing economic climate

• 24/7 Risk Management: Our platform monitors market dynamics around the clock, automatically rebalancing your asset allocation in real-time as economic regimes shift. This ensures effective risk control while eliminating the bias of human emotion from your investment strategy.  

• Low Barriers, High Efficiency: Management fees are as low as 0.2% p.a., with no minimum investment and no lock-ins for most portfolios.

資料來源：

1. WeLab Bank，《貨幣市場基金，係咪值得繼續投資？》https://www.welab.bank/zh/blog/gowealth_insights/is-it-worth-continuing-to-invest-in-a-money-market-fund/

2. Congress.gov, “Money Market Mutual Funds: Policy Concerns and Reform Options”https://www.congress.gov/crs-product/R47309

3. 香港特別行政區政府新聞公報，《二零二零年十二月份消費物價指數》https://www.info.gov.hk/gia/general/202101/21/P2021012100401.htm