Fed raises rates again — why this is the perfect time to open a flexible CD

On Wednesday, the Federal Reserve announced a quarter-percentage point increase in its benchmark interest rate, bringing it now above 5%. This rate hike marks a 16-year high and the 10th consecutive raise since the Fed began raising rates from near zero in March 2022.

The top high-yield savings accounts have already been offering an APY as high as around 5% to 6%, but some CDs are worth savers' attention, as well — especially in a changing-rate environment. We're specifically talking here about flexible, or "flex," CDs.

This type of CD differs from the standard CD in that it offers savers more freedom with their money, whether that be the ability to score a variable rate rather than a fixed one, to opt into a higher rate when offered during the CD term or to pull out your cash at no cost. If the Fed does indeed pause future rate hikes, which has been signaled, this last option is helpful if you want to move your cash elsewhere with a better return.

Banks may use the term "flex CD" differently, but these CDs can typically be grouped between three categories: variable-rate CDs, bump-up CDs and no-penalty CDs. Below, CNBC Select breaks down what you need to know about their offerings and how they can help you during this time.

Variable-rate CDs are similar to traditional CDs in that they lock up your money for a fixed term, but instead of offering a fixed interest rate for the length of the term, they offer a fluctuating rate that can go up and down at any time — including when the Fed makes changes to their benchmark rate. This means they're a natural pick in a rising-rate environment, but less so when rates go down.

For example, the Merchants Bank™ of Indiana Flex Index CD immediately allows deposit account holders to earn more when the Fed raises rates. The bank is currently offering a generous 5.39% variable APY, and savers can choose from a 12-month, 24-month or 36-month CD term. There is a minimum $1,000 deposit required to open an account and to earn the high APY, but this benefits you in the end; the greater your balance the likely higher earnings you'll have. There may be a penalty for early withdrawal.

Bump-up CDs can be considered a type of variable-rate CD. These CDs allow savers to take advantage when interest rates rise, aka now. Normally, you would be locked into a fixed interest rate, but a bump-up CD allows you to ask the bank for a higher rate if they end up offering one during your term.

For example, if you opened a three-year CD, and after one year the bank raises the interest rate offered on that product, you could opt into that higher rate for the remaining two years of your term.

Most banks offering bump-up CDs only allow you to opt-in once per CD term. Before choosing a bump-up CD, make sure to also compare the starting APY to the bank's traditional CD's APY. If it's lower, then you may end up just bumping the APY to the traditional CD rate down the road.

You may also come across step-up CDs, which are similar to bump-up CDs, with the caveat that the bank automatically raises your interest rate to the new, higher yield at specific times during your loan term. Savers don't need to ask the bank in order to opt in to the higher rate.

Some banks that offer bump-up CDs include Ally Bank, Marcus by Goldman Sachs and Synchrony Bank, but as with variable CDs, they're generally harder to find than other types of CDs.

If you're worried about not being able to tap into your savings in this uncertain market or if rate increases stop and you want to put your cash into a higher-earning account, a no-penalty CD can help. No-penalty CDs are more convenient than traditional CDs, allowing you to easily withdraw money before your CD term ends without having to pay the typical penalty fee.

There are still some withdrawal rules: Most banks have timeline requirements that prevent you from withdrawing penalty-free for at least seven days after you open the account.

Gordon Achtermann, CFP at Your Best Path Financial Planning, recommends no-penalty CDs when saving up or the short term, such as a year or less because you can access your money on a whim.

For example, the Ally Bank® No Penalty CD. There's no minimum deposit required to open an account and you can withdraw your full balance and interest any time after the first six days of funding your CD.

No-penalty CDs often come with lower interest rates, which is something to take into account before opening one. If you really think you'll need access to your cash, you may be better off putting it into a high-yield savings account.

With some standout high-yield savings reaching 5% APY — and even 6% APY in some cases — CDs may not always have the upper hand. Here are some of the highest-paying accounts:

Treasury bills, or T-bills, are another option to consider. They're nearly risk-free and highly liquid, which means they're very safe places to park the cash you'll need soon. Keep in mind, however, that T-bill returns typically react inversely with the Fed benchmark rate; a higher rate set by the Fed means lower returns on T-bills. In contrast, high-yield savings and CDs usually raise their rates as the benchmark rate goes up. For this reason, T-bills may be a good option if rates stop rising.

You can purchase T-bills directly from the government via TreasuryDirect.gov or through brokerages like Fidelity and Charles Schwab.

A flex CD offers flexibility when it comes to wanting to earn a higher return as the Fed raises rates or wanting to access your cash with no penalty if rate hikes stop. Shop around to choose the best CD for you.

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