Earn Interest Even for a Single Day: How to Make the Most of CMAs and Parking Accounts
Suppose your salary comes in on the 25th and your credit card bill is withdrawn on the 14th of the following month. For those roughly three weeks, the money sitting in your account is “idle cash.” If you leave it in a regular checking account, the annual interest rate is around 0.1%, which means you effectively earn almost no interest. If you place the same money in a CMA or a parking account, interest accrues daily. This article is not a recommendation for any specific product, but a reference guide to help you understand, with numbers, the structure of managing short-term spare cash.
| Section | Key summary |
|---|---|
| Introduction | Main context in brief |
| How are CMAs and parking accounts different? | CMA-RP type (securities firm): Managed through repurchase agreements |
| The trap of “preferential rate limits” and “special promotions” | Short key point |
| Understand taxes and comprehensive taxation on financial income | Short key point |
| Money you should not put in a parking account | Short key point |
Why does interest accrue “even for a single day”?
How are CMAs and parking accounts different?
- Parking account (bank): If it is covered by depositor protection, check the combined principal-plus-interest limit of 100 million won per person, per financial institution. These accounts are usually “tiered-limit” products, meaning the preferential rate applies only up to a certain balance, while any excess receives the basic rate.
- CMA-RP type (securities firm): Managed through repurchase agreements. It is not covered by depositor protection, but because it is backed by high-grade bonds, it is generally classified as relatively stable.
- CMA issued-note type: Issued by comprehensive financial investment businesses that meet a certain equity-capital threshold. Not covered by depositor protection.
- CMA-MMF/MMW type: Linked to market interest rates. It does not offer a fixed rate; returns vary slightly from day to day depending on management performance.
Calculating actual interest with numbers
Does it matter even with a small amount?
The trap of “preferential rate limits” and “special promotions”
- Define the purpose: Separate only money that you may need soon, such as emergency funds or short-term waiting cash, for parking.
- Check protection: If safety is your top priority, use a bank parking account covered by depositor protection and stay within the 100 million won limit.
- Check the rate structure: Calculate the rate that actually applies to your amount and your period, not just the displayed rate.
- Reflect taxes: Remember that the real return is the pre-tax rate × 0.846, after deducting 15.4%.
- Diversify: If the amount grows large enough to exceed the 100 million won limit, splitting it across financial institutions and checking each depositor protection limit can be an option.
Understand taxes and comprehensive taxation on financial income
Money you should not put in a parking account
In short, CMAs and parking accounts are tools for temporarily and safely managing money you will need soon. Instead of looking only at advertised rates, calculate the rate that actually applies to your amount and holding period, and consider depositor protection and taxes (15.4%) together. The figures in this article are examples for easier understanding, and actual rates and conditions vary by product and timing. Before signing up, be sure to check each financial institution’s product disclosure documents. (This content is for informational reference only and is not a recommendation to invest in any specific product.)