Splitting a Lump Sum of 30 to 100 Million KRW

Three things to check when splitting a lump sum

Up to what amount the high rate applies

Many parking accounts do not apply the same rate to the whole deposit. Some pay the high rate only up to a certain amount, and others raise the rate only above a certain amount.

전북은행 씨드모아통장 splits by amount into a small-balance tier and a large-balance tier. The small-balance tier applies the preferential rate to balances of 50 million KRW or less; the large-balance tier applies it to the entire deposit when it is 50 million KRW or more. 케이뱅크 플러스박스 applies 1.70% per year up to 50 million KRW and 2.20% per year to the portion above it.

With 80 million KRW, for example, the calculations diverge. 씨드모아’s large-balance tier applies the same preferential rate to all 80 million KRW when the conditions are met. 케이뱅크 calculates 1.70% per year on 50 million KRW and 2.20% per year on the remaining 30 million KRW separately.

For a lump sum, comparing what you will actually receive means checking not only what the maximum rate is but how much of your money it applies to.

How much you can put in one place

The depositor protection limit is 100 million KRW per person per financial institution, covering principal and interest combined. It has applied since September 1, 2025, and money spread across several accounts or branches of the same bank is still counted together.

So depositing exactly 100 million KRW of principal does not mean the interest to come is also protected. Because the limit covers interest as well as principal, when depositing close to 100 million KRW it is better to set the principal with the expected interest already calculated.

If you already hold other deposits or installment savings at the same bank, check those amounts too. The limit is 100 million KRW per institution, not per account.

Whether you can open the same product more than once

If the preferential rate has a usage limit, opening several accounts does not let you receive the same preferential rate repeatedly.

씨드모아’s maximum 4.00% per year (before tax) applies for three months after opening, once per customer. Splitting a lump sum across several accounts does not earn the 4.00% preferential rate on each of them.

So if you plan to divide the money, check each product’s deposit cap and how many times the preferential rate can be used. If you have already used one product’s preferential rate, recalculate the remainder at the rate you would actually receive in another product.

Allocation by amount

30 million to 50 million KRW

At this size there is no need to split across institutions for depositor protection. 씨드모아’s small-balance tier applies its preferential rate to balances of 50 million KRW or less, so in this band the entire deposit qualifies.

Held for three months, 30 million KRW gives after-tax interest of 255,885 KRW with 씨드모아’s small-balance tier. To hold it without preferential conditions, SBI저축은행 사이다입출금통장 gives 172,723 KRW at 2.70% per year and 케이뱅크 플러스박스 gives 108,751 KRW.

케이뱅크 플러스박스’s 2.20% per year applies only above 50 million KRW. So while you hold 30 million to 50 million KRW, calculate on the basis of 1.70% per year.

At 50 million KRW or less, rather than splitting money for depositor protection, check first whether you can actually receive the preferential rate and how long the preferential period runs.

50 million to 100 million KRW

Above 50 million KRW the products differ more in how they apply the rate.

씨드모아’s large-balance tier applies up to 4.00% per year to the entire deposit of 50 million KRW or more when the conditions are met. 케이뱅크 플러스박스, by contrast, splits the calculation at 50 million KRW.

Held for three months, 80 million KRW gives after-tax interest of 682,362 KRW with 씨드모아’s large-balance tier. SBI 사이다입출금통장 continues at 2.70% per year up to 100 million KRW for 460,595 KRW, and 케이뱅크 플러스박스 applies 1.70% per year to 50 million KRW and 2.20% per year to the remaining 30 million KRW for 321,989 KRW after tax.

As the amount approaches 100 million KRW, calculate the depositor protection limit with the interest included. Applying 4.00% per year as a simple calculation, 96 million KRW of principal held for a year produces 3.84 million KRW of interest before tax. Principal plus interest comes to 99.84 million KRW, which stays within 100 million KRW.

Note that 씨드모아’s 4.00% per year applies only for three months after opening, so this example is not a specific product’s actual one-year receipt but a simple calculation used to explain the depositor protection limit.

Above 100 million KRW

A lump sum above 100 million KRW is safer split across institutions than held in one. Depositor protection covers 100 million KRW of principal and interest combined per institution, so anything beyond that falls outside the covered range.

Taking 150 million KRW as an example, you could put 96 million KRW in 씨드모아 and the remaining 54 million KRW at another institution. 씨드모아’s maximum 4.00% preferential rate applies once per customer, so the same terms cannot be applied again to a second account. The remainder has to be compared separately against other products such as 케이뱅크 플러스박스.

200 million KRW and above

At 200 million KRW and above, splitting across three or more institutions is also worth considering. With 200 million KRW, for example, that could mean 96 million KRW in 씨드모아, 96 million KRW in 케이뱅크, and the remaining 8 million KRW in 카카오뱅크 세이프박스.

The more institutions involved, the more separately you have to check each product’s preferential conditions and deposit bands. For money you have no plans to use for a year or more, comparing time deposit rates is better than putting the whole amount in parking accounts.

Interest received over three months

씨드모아’s preferential rate applies for three months after opening, so the comparison period is set to three months as well.

Interest before tax is the principal multiplied by the annual rate, multiplied by the number of days held, divided by 365. Interest income tax of 15.4% under standard taxation is then deducted. For 케이뱅크 the calculation is split, applying 1.70% per year up to 50 million KRW and 2.20% per year above it.

씨드모아 splits into a small-balance tier and a large-balance tier at 50 million KRW, but the maximum rate for both is 4.00% per year (before tax, as of July 2, 2026). The table therefore applies the matching tier to each deposit amount and calculates at the same rate.

케이뱅크 applies a higher rate to the portion above 50 million KRW. At 30 million KRW the whole amount earns 1.70% per year; at 100 million KRW, 50 million KRW earns 1.70% per year and the remaining 50 million KRW earns 2.20% per year.

Calculating the 100 million KRW protection limit

The limit is based on principal and interest combined, not principal alone. So the maximum principal you can deposit changes with the rate that applies.

Protected interest is actually calculated using the lower of the agreed rate and the rate set by the Korea Deposit Insurance Corporation. The table above is a simple calculation applying the product rate as it stands, so it may differ from the amount actually protected.

If you would rather not work through the arithmetic, treat it as setting the principal a little lower the higher the rate is. At 4.00% per year, around 96 million KRW, and at 1.60% per year, around 98 million KRW, keeps the total within 100 million KRW including interest.

Conversely, depositing a full 100 million KRW of principal at 4.00% per year for a year adds 4 million KRW of interest before tax, bringing principal and interest to 104 million KRW. In that case the portion above 100 million KRW falls outside the covered range.

How interest changes when you split the money

Splitting across institutions widens the covered range, but it can make it hard to apply the high rate to the whole amount. Products such as 씨드모아, where the preferential rate is limited to once per customer, require the remainder to be placed at another product’s rate.

Taking 150 million KRW held for one year as a simple comparison, splitting into 96 million KRW at 씨드모아 and 54 million KRW at 케이뱅크 gives after-tax interest of 4,042,188 KRW. Assuming 4.00% per year applied to all 150 million KRW for a year, after-tax interest would be 5,076,000 KRW.

The difference between the two calculations is 1,033,812 KRW. On the other hand, holding all 150 million KRW at one institution puts 56 million KRW of the 156 million KRW in principal and interest beyond the depositor protection limit.

Note that this comparison is a simple calculation assuming 4.00% per year holds for one year. 씨드모아’s preferential rate applies only for three months after opening, so an actual one-year comparison has to include the base rate that follows.

Before you allocate

Decide the total amount first. The conditions to compare differ between depositing 30 million KRW and 150 million KRW. Setting the total and then dividing it to fit each product’s deposit bands and protection limit makes the arithmetic easier.

Check the limit on how many times the preferential rate can be used. With products limited to once per customer, opening several accounts does not earn the same preferential rate repeatedly. The remainder has to be recalculated at another product’s actual rate.

Count existing deposits as well. Depositor protection applies per institution, not per account. If you already hold a time deposit, installment savings or a demand account at the same bank, check those amounts too.

Set the principal with interest included. Depositing 100 million KRW of principal alone can push you past the protection limit once interest accrues. For money you plan to hold for a long time, leave room for the expected interest when setting the principal.

If the spending date is fixed, compare time deposits too. A parking account lets you take the money out when you need it, but there is no guarantee the rate will hold. If you have no plans to use the money for a year, compare it against a time deposit where the rate is fixed.

Frequently asked questions