What is the difference between FX and foreign currency deposits? Mechanisms, costs, and risks that FX beginners want to know

The difference between FX and foreign currency deposits is whether you hold foreign currency with the full amount of your money on hand or trade by depositing margin. I will explain the differences in whether you can only buy or also sell, as well as costs and the handling of deposit insurance for FX beginners (as of October 2026).

I am Yamamoto, an asset-building FX warrior.
I have spent 10 years facing my PC and monitors intently. I lived almost like a hermit, but thanks to AI, I have gained some time, so I am writing here about the market I have observed.

This is the 40th installment of the FX introductory series. This time, it is about the “difference between FX and foreign currency deposits,” which are often compared.

What is the difference between FX and foreign currency deposits?

In a nutshell, it is the difference between “holding foreign currency with the full amount” and “trading by depositing collateral.”

A foreign currency deposit is a product where you exchange yen for foreign currency and deposit it in a bank or similar institution. If you deposit 1,000 dollars, you pay the yen equivalent of 1,000 dollars.

FX is a transaction where you put margin (money deposited as collateral) into an account and buy and sell currencies. You do not need to pay the full amount of the transaction.

Both are the same in that the amount when converted back to yen changes due to exchange rate fluctuations. What differs is how the money is moved and the magnitude of the risk.

Another point is that while foreign currency deposits only involve buying and holding foreign currency, FX also allows you to start by selling. While you can aim for profits when the yen strengthens, the scenarios where you incur losses when you are wrong also increase.

When comparing USD/JPY, how do the profit/loss and required money differ?

In a nutshell, “even if the profit/loss from price movements is the same, the money you need to prepare is different.”

To make it easier to calculate, I will compare using hypothetical numbers without considering costs such as fees.

1. Suppose you hold 1,000 dollars worth when USD/JPY is 150 yen.
2. With a foreign currency deposit, you pay 150,000 yen (150 yen x 1,000 dollars).
3. If you buy 1,000 currency units in FX, what you pay is a margin that is a portion of the 150,000 yen.
4. When USD/JPY becomes 151 yen, both result in a profit of 1,000 yen (1 yen x 1,000).
5. When it becomes 149 yen, both result in a loss of 1,000 yen.

https://money.note.com/indices/USDJPY

Even if the profit and loss from price movements are the same, FX allows you to trade with the same magnitude using less money. This is leverage. Since the ratio of loss relative to the money in your account becomes larger, that is the biggest difference from foreign currency deposits. The topic of leverage is summarized in the third section.

How do the costs and the way ‘interest’ is received differ?

In a nutshell, ‘foreign currency deposits earn interest, while FX earns swap points’.

With foreign currency deposits, there is a currency exchange fee when converting between yen and foreign currency. While the money is deposited, you receive interest based on the foreign currency’s interest rate.

In FX, the spread, which is the difference between the buying price and the selling price, becomes the cost for each trade. The difference in interest rates is received or paid daily as swap points.

Swap points can sometimes become a payment on short positions.

How is deposit insurance handled differently?

In a nutshell, ‘even though foreign currency deposits are deposits, they are not covered by deposit insurance’.

Deposit insurance is a system that protects deposits within a certain range when a bank or similar institution fails. According to the Deposit Insurance Corporation of Japan, foreign currency deposits are listed as deposits not covered by deposit insurance.

Even if it has ‘deposit’ in the name, it is not protected in the same way as a yen savings account.

Whichever you choose, it is important to check the mechanism by which the company where you deposit your money manages it.

Why is it important? My thoughts after watching monitors for 10 years

In a nutshell, it is because ‘even with the same currency, the magnitude of the risk you bear is different’.

Foreign currency deposits and FX are both the same in that you are putting money on currency price movements. However, the speed at which losses grow in the account is completely different.

For 10 years in front of my monitors, I have always first checked [what I am putting money on, and how much]. My method is to look at the size of the potential loss before the name of the product.

It is not a matter of which one is better. Choose the size you can bear. Do not misjudge that.

Frequently asked questions about FX and foreign currency deposits

Q. Which is more suitable for beginners, FX or foreign currency deposits?
A. It depends on your purpose and the size of the loss you can bear. Note that while FX allows you to trade with a larger volume using less money, losses can also easily become larger.

Q. Is the principal of foreign currency deposits guaranteed?
A. It is not guaranteed. If the yen strengthens, the amount you get back when converting to yen will decrease. According to the Deposit Insurance Corporation of Japan, foreign currency deposits are not covered by deposit insurance.

Q. Can I make a profit in FX when the yen strengthens?
A. If you enter a position by selling, you can make a profit when the yen strengthens. However, if the yen weakens contrary to your expectations, you will incur a loss.

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The FX introductory series is being expanded little by little every day.
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In FX, losses can exceed the principal. Please make your own trading decisions.

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