If you want to earn the highest interest rates on your bank deposits, a high-yield savings account (HYSA) is often the way to go. Depending on the particular account, your rate can be as much as 20 times higher than the national average rate for a traditional savings account.

Yet, there's an important feature of HYSAs that many people overlook: The interest rates aren't set in stone. Like many other types of bank accounts, high-yield savings account rates can change at any time, at the discretion of the financial institution.

Does that mean you should ditch your HYSA in favor of fixed rates? Not necessarily.

The interest rates on high-yield savings accounts are variable, which means they can change at any time. In fact, if you look at the bank disclosures for your HYSA, you'll probably see a line that says something like, "Interest rate may change at any time without notice."

Does that mean your HYSA rate will take a major dip after you open it? Probably not. Many banks set competitive rates for these accounts in order to attract and keep your business, and they don't want to drive you and your money away with abrupt changes.

When HYSA rates change, the adjustments are more likely to be incremental. For example, in July 2024, the highest rate we could find on a high-yield savings account was 5.36% APY. After almost a year, the best high-yield savings accounts offer rates roughly one percentage point lower (up to 4.30% APY). But this is still quite high by historical standards.

Additionally, if the rate on your HYSA drops, it should still pay more than you earn on other deposit accounts at the same bank. That's because banks want to incentivize you to leave your money on deposit for the long term.

Read more: Fixed rate vs. variable rate: What's the difference, and why is it important?

If the interest rate on your HYSA changed, it's most likely due to monetary policy decisions by the Federal Reserve. But that's not the only explanation for a rate shift. Here are three main reasons why high-yield savings account rates change:

• Federal Reserve policy: Banks usually adjust rates in accordance with the benchmark federal funds rate. The Fed meets eight times a year to set rate policies — and if a rate change is announced, it can take anywhere from weeks to months for your bank to update the interest rate on your HYSA.

• Bank policy: Banks often increase rates to stand out from the competition and attract new customers and more deposits. For example, if your bank has a high demand for loans, it may increase its HYSA rate to bring in more deposits so it has the funds to back those loans.

• Rate tiers: Some HYSAs have rate tiers, which means the interest rate is based on your account balance. If your balance increases or drops on a tiered HYSA account, your interest rate can change.

Keep in mind that your bank isn’t required to provide you with notice of upcoming rate changes, so you may not find out until you see the new information on your bank statement. You can also stay up-to-date on Fed news to anticipate when a rate change could be coming.

Read more: How do banks set their savings account interest rates?

When your HYSA rate drops, your knee-jerk reaction might be to look for a new account. But first, take a pause.

Unless you have a large amount on deposit or the rate drops sharply, the impact on your earnings is likely small.

For example, if you have $25,000 in a savings account that earns 4.5% APY with daily compounding interest, your account balance will reach $26,125 after one year. But if that rate drops to 3% APY, the balance will reach $25,750 in one year. That's only a difference of $375.

Read more: Is ‘rate chasing’ worth it?

With that said, it's always wise to keep an eye on what banks are offering. Whether or not your HYSA rate has dropped, you may find another account that's worth the time and effort of switching banks. Here's what you should look for to find the best HYSA:

• Rates: Check out online banks, credit unions, and community banks to find the highest available rates.

• Fees: Avoid accounts with maintenance fees or minimum balance fees, since they'll eat away at your earnings.

• Deposit requirements: Make sure you can easily meet the deposit requirements, which might include an opening deposit requirement and an average daily deposit needed to qualify for the highest rate.