Guide to Add-On Certificates of Deposit

By Rebecca Lake · May 02, 2022 · 9 minute read

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Guide to Add-On Certificates of Deposit

A certificate of deposit (CD) can be a good savings vehicle, and an add-on CD can be even better if you crave more flexibility. Traditional CDs are time-deposit accounts that allow you to save money for a set term while earning interest. Typically, when you open a CD, you’re locked in for a period of time.

But add-on CDs offer a convenient twist on that basic principle: They are CDs which permit you to deposit additional funds after the account is opened.

Banks and credit unions can offer add-on CD accounts alongside other types of CDs. Whether it makes sense to open an add-on CD can depend on your financial goals. To help you understand how these accounts work and whether they are right for you, we’ll cover the following:

•  What an add-on CD is

•  How an add-on CD compares to a traditional CD

•  The pros and cons of an add-on CD

What Is an Add-On CD?

CD accounts are designed to help you save money that you can afford to “lock up” for a period of time. Generally, when you open a CD account, you make an initial deposit. That deposit earns interest throughout the CD’s term until it matures, or becomes accessible again. The term can be anywhere from a month to 10 years, but many people opt for a couple or a few years.

Once the CD matures, you can withdraw your initial deposit and the interest earned or roll the entire amount into a new CD. These are generally low-risk investments. There’s virtually zero possibility of losing money since you know the interest rate from the start and the funds are FDIC-insured.

Add-on certificate of deposits, sometimes referred to as add-to CDs, give you the option to make additional deposits to your CD after opening the account. So, for example, you might open an add-on CD with an initial deposit of $500. You might then choose to deposit $100 per month into the CD account for the remainder of the maturity term.

The bank or credit union with which you open the add-on certificate of deposit account might require additional deposits to be made via automatic transfer. There may also be a minimum amount that you’re required to deposit monthly or bimonthly.

How an Add-On CD Works

An add-on certificate of deposit account works much the same as any other CD, with one exception: You can make additional deposits to the account. Opening an account for a CD add-on starts with choosing a CD term. This is the length of time you’ll leave the money in your account.

Choosing the right term for an add-on CD matters for two reasons. First, it can determine how much interest you’ll earn on deposits. The longer the term, the more time your money has for compound interest to accrue. Banks and credit unions may also reward you with a higher interest rate and annual percentage yield (APY) for choosing a longer add-on CD term.

Second, you need to be fairly certain that you won’t need to withdraw money from an add-on CD account before it matures. Banks can impose penalties for early CD withdrawals, which can be equivalent to some or all of the interest earned. The penalties might even take a bite out of your principal.

Once you choose an add-on CD to open, you can complete the application and make the initial deposit. The amount required to open an add-on certificate of deposit accounts can vary from bank to bank. It’s typically less than for a traditional CD; perhaps $100. You can also decide how much you’d like to contribute to your add-on CD each month going forward.

As you make new deposits to your add-on CDs, that amount gets added to the principal and earns interest. You’ll then earn interest on the principal and interest as the CD compounds over time.

Recommended: How Long Does it Take to Open a New Bank Account?

Can You Add Money to a CD Before It Matures?

Generally, you cannot add money to a traditional CD beyond the initial deposit you make when you open the account. Once the CD reaches maturity, your bank may allow you a grace period of 7 to 10 days in which you can make new deposits to the account. You might choose to add money during the grace period if you plan to roll the funds into a new CD account.

Add-on CDs give you more flexibility since you’re not bound by such strict rules for deposits. You can set up additional deposits to your CD to continue growing your balance, based on an amount that fits your budget and savings goals. You could even take investing in CDs a step further and create a CD ladder.

A CD ladder strategy involves opening multiple CDs, add-on or otherwise, with varying maturity terms and interest rates. Rolling maturity dates mean you may not have to worry about triggering early withdrawal penalties if you need cash. Why? Because with the staggered terms, you can always have a CD getting close to its maturity. This means you’re likely to soon have access to your cash. Laddering also allows you to take advantage of interest rate hikes if they occur.

Add-on CD vs. Traditional CD

You might consider add-on CDs and traditional CDs if you’re comparing different types of high-interest accounts. Either type of CD could help you to achieve your short- or long-term savings goals. Before opening an add-on or traditional CD, it helps to know how they compare.

•  Add-on CDs allow you to add money after account opening; traditional CDs do not.

•  Minimum deposit amounts may be lower for add-on certificate of deposits versus traditional CDs.

•  Banks may offer different interest rates for add-on CDs vs. traditional CDs.

•  Different early withdrawal rules and penalties may apply.

When deciding where to open a certificate of deposit account, first consider whether add-on CDs are an option. Then you can look at the interest rates offered and the CD terms available.

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Advantages of Add-On CDs

Opening an add-on certificate of deposit account is something you might consider if you’re looking for something other than a traditional CD or a more flexible financial vehicle. Understanding the benefits of add-on CDs can help you decide if this is the right savings option for you.

Low Minimum Deposit

CDs impose a minimum deposit requirement; otherwise, you’d have no money to earn interest on. These minimums are often around $500 or $1000 or more. Banks may offer lower initial deposits for add-on CD accounts to get you to open them and continue depositing money later. You might find ones in the $100 range. That can be an advantage if you want to save with CDs but you don’t have a large amount of money in your bank account to deposit up front.

Guaranteed Return

If you’re looking for safe investments, it doesn’t get much safer than CDs. Add-on CDs can offer a guaranteed return for your money since you’ll know what the interest rate and APY are before opening the account. You can then use a CD calculator to estimate how much of a return you’ll get for your money over the maturity term.


Perhaps the biggest advantage of add-on CDs is the flexibility they offer. With a traditional CD, you make one deposit and that’s it. You can’t add anything else until the CD matures. An add-on CD, however, gives you the option to continue saving at a pace you can afford.

Disadvantages of Add-On CDs

Add-on CDs have some attractive features but they aren’t necessarily right for everyone. There are few potential drawbacks to keep in mind if you’re debating whether an add-on CD account might fit into your savings plan.

Lower Rates

Banks may offer lower interest rates for add-on CDs and reserve higher rates for traditional CDs with longer terms. When comparing add-on CDs, consider the different rates you might get at traditional banks vs. online banks. An online bank may be the better choice if you’re hoping to get the highest rate possible for add-on CDs. Or check and see what kinds of interest rates are being offered on high-yield savings accounts. You might find you fare better with one of those.

Early Withdrawal Penalties

Add-on CDs allow you to add money on your own terms but there are restrictions on when you can take money back out. Remember, the bank can charge an early withdrawal penalty if you decide to pull money from your CD before maturity. Penalties could cost you some or all of the interest earned.

Guaranteed Return

An add-on CD can offer a guaranteed return but it might not match the return you could by investing your money elsewhere. Trading stocks, exchange-traded funds (ETFs), or IPOs, for example, could yield a better return on your money if you’re comfortable taking more risk.

Example of an Add-on CD

Now that you know the pros and cons of add-on CDs, let’s zoom in on how exactly one might be set up to help you save. Say you want to open a 12-month CD. You find a bank offering add-on CDs with a $100 initial deposit. You open the CD account with $100, then set up an automatic deposit of $100 monthly. Throughout the CD term, you’ll earn an APY of 0.40%.

At the end of the CD term, the bank gives you the option of rolling your initial deposit, monthly deposits, and interest earned into a new add-on CD or cashing it out. Since interest rates have increased during the maturity term, you decide to roll it into a new add-on CD with a 12-month term. You continue making $100 monthly deposits as scheduled, only now you’re earning a 0.55% APY instead. As you can see, you’re bulking up your savings, and the interest is compounding and rising. A win-win situation.

The Takeaway

Add-on CD accounts can help you reach your savings goals while offering more flexibility than other CDs. Before opening an add-on CD, it’s helpful to shop around to see which banks or credit unions offer them and how much interest you might be able to earn. Check into the minimum deposit required, different term lengths, and current interest rates to find the best match for your needs and financial goals.

While shopping for ways to grow your savings, you might want to also consider banking with SoFi. Our online banking platform gives you two kinds of linked accounts – checking and savings. When you sign up with direct deposit, you’ll get access to your paycheck up to two days early, earn a competitive APY, and you won’t pay any monthly or minimum balance fees.

Shouldn’t your money work harder for you? At SoFI, it does.


What is an add-on CD?

An add-on CD is a certificate of deposit account with more flexibility. It allows you to make additional deposits after the CD has been opened. Banks may impose a minimum deposit requirement, and you may need to automate deposits to add-on CDs.

Can you add additional funds to a CD?

CDs typically do not allow you to make additional deposits once your CD account has been opened. Add-on CDs, however, are designed to allow additional deposits before the CD matures.

Photo credit: iStock/Atstock Productions

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