【summary】
Mini stocks, or more precisely fractional shares, are a service that allows you to buy Japanese stocks in units of 1, which are normally bought and sold in units of 100.
If a stock has a stock price of 5,000 yen, you would need 500,000 yen to invest 100 shares normally. You can purchase shares of less than one unit for as little as 5,000 yen. It is easy to use for people who want to familiarize themselves with Japanese stock price movements, dividends, financial results announcements, and securities account operations before investing a large amount of money.
However, as convenient as it is, there are some caveats. The stocks you can order, execution timing, commissions, spreads, and NISA treatment differ depending on the securities company. It is best not to think of shareholder benefits and voting rights in the same way as a unit of 100 shares or more.
| What to look at first | Guidelines for judgment |
|---|---|
| Investment amount | Don't concentrate on one stock, try starting with one stock |
| Securities company | Check commissions, spreads, order times |
| Account classification | Choose between a specific account or NISA growth investment limit |
| Stocks | View from the perspective of large stocks whose business is easy to understand |
| Risk | Even if the amount is small, there is a risk of stock price decline, dividend reduction, and bankruptcy |
This article is intended for general investment education and does not recommend the use of any particular securities company or stock. Fees, transaction rules, and NISA compliance are subject to change, so please check the latest terms and conditions on each company's official page before placing an order.
What are mini stocks and shares less than one unit?
For many Japanese stocks, one unit is set at 100 shares.
For example, if the stock price is 5,000 yen, the following funds are required for normal unit stock trading.
5,000円 × 100株 ＝ 500,000円On the other hand, there are services that allow you to purchase shares of less than one unit from just one share.
| How to buy | Example of required funds |
|---|---|
| 100 shares | 500,000 yen |
| 10 shares | 50,000 yen |
| 1 share | 5,000 yen |
It's scary to put 500,000 yen into one stock from the beginning. This isn't just for beginners. Stock prices may drop due to financial results, and dividend policies may change. If you can buy from 1 share, you can gradually get used to it while watching the actual price movements.
First conclusion: Beginners should start in this order.
The process to start holding fractional shares is not difficult.
- Open a securities account
- Check the specific account or NISA account
- Search for stocks eligible for less than one unit service
- Start by ordering 1 share
- Check the contract price, commission, and how dividends are paid
- Once you get used to it, consider buying more or diversifying.
You don't have to worry about creating a high-dividend stock portfolio from the beginning. First, you buy one share and look at the unrealized profit/loss, dividend schedule, and financial results news from the next day onwards. You can learn a lot there.
Advantages of fractional unit shares
1. You can get exposure to Japanese stocks from a small amount
The biggest advantage of fractional unit shares is that the required capital can be lowered.
You can buy a stock with a stock price in the 1,000 yen range for a few thousand yen, and even a stock with a stock price in the 5,000 yen range for a few thousand yen. Even if it is a large stock that is difficult to get into with 100 stocks, it is easy to try one stock.
2. Easy to disperse
Instead of putting 50,000 yen into one stock, you can divide 10,000 yen into 5 stocks, or several thousand yen into 10 stocks.
Diversification does not mean that you will not lose money. However, it will be easier to avoid a situation where the entire fund is affected by bad news from one company.
3. Easy to combine with NISA growth investment limit
Starting in 2024, NISA will allow you to use both the accumulation investment limit and the growth investment limit. The Financial Services Agency explains that sales profits, dividends, and distributions obtained from financial products invested in NISA accounts will be exempt from tax.
Depending on the securities company, shares of less than one unit can also be traded under the NISA growth investment limit. It is convenient for people who want to try individual stocks with a small amount.
However, the products that can be purchased with NISA vary depending on the financial institution. Even if you incur a loss, don't forget that with a NISA account, you cannot aggregate profits or carry forward deductions.
Disadvantages and precautions
1. Order timing is more limited than regular stocks
For a normal 100 stock trade, it is easy to place a limit order or market order during trading hours.
For shares of less than one unit, the order time and execution timing are determined by each securities company. Some services allow you to buy and sell in real time, but there may be a spread. It is not suitable for people who want to buy and sell in detail while watching stock prices.
2. You need to understand fees and spreads
Even if it says ``no buying fees,'' you'll want to check the selling fees, spreads, phone order fees, conditions for NISA accounts only, etc.
For small investments, even costs of a few tens of yen will result in a large return. Rather than buying and selling just one stock frequently, it's easier to wait a little before buying and not buy too many times.
3. Shareholder benefits and voting rights are not the same as 100 shares
Dividends are often received based on the number of shares held.
On the other hand, voting rights are usually based on one unit or more. There are also many conditions for shareholder benefits, such as ``100 or more shares'' and ``holding for more than 1 year.'' It's dangerous to think that you can get preferential treatment just by buying one share.
Service name of major online securities companies
In typical online securities companies, each fractional unit share service has its own name.
| Securities company | Service name | Points to check |
|---|---|---|
| SBI Securities | S shares | Fees, order time, handling under NISA |
| Rakuten Securities | Kabumini® | Donation trading, real-time trading, and spread |
| Monex Securities | One share | Trading fees, execution timing, NISA compatibility |
Official information available as of June 5, 2026 states that SBI Securities' S shares are free of purchase and sale fees when traded online. Rakuten Securities' Kabumini® has no purchase fees, but there is a 0.22% spread in real-time trading. There is no purchase fee for Monex Securities' 1 share, 0.55% sales for general and specific accounts and a minimum of 52 yen, and no trading fees for NISA accounts.
This condition is subject to change. I would like to check the order screen and official rules of the securities company I will actually use, rather than just making a decision based on the comparison table.
How to buy
STEP1 Open a securities account
First, open a general securities account with an online securities company.
At this time, if you select ``withholding tax'' for a specific account, the securities company will generally calculate the tax for you, making it easier for beginners to manage. If you use NISA, you will also need to open a NISA account. It is also important to note that there is only one NISA account per person, and changes in financial institutions are required on an annual basis.
STEP2 Deposit
An initial deposit of 10,000 yen to 50,000 yen is sufficient.
The important thing here is not to include money that you plan to use in the near future for living expenses. Even if you invest a small amount, loss of principal will occur as long as it is a stock.
STEP3 Select a brand
Beginners don't have to suddenly go into small-cap stocks that they have never heard of.
At first, it's easier to understand what you're buying if you look at the following stocks.
| Perspective | Example |
|---|---|
| Companies I use regularly | Telecommunications, food, retail, railways, etc. |
| Companies whose performance is easy to follow | Large stocks whose financial statements are easy to read |
| Companies whose dividends are easy to check | Companies whose dividend policy and dividend results are made public |
| Companies whose price movements are not too drastic | Not biased toward theme stocks or low-ranking stocks |
Just because it's a famous company doesn't mean it's safe. Large stocks will also fall. The important thing is whether you can track down the reason for the decline.
STEP4 Order as less than one unit
On the order screen, instead of the usual spot stocks, you can choose from screens such as fractional shares, S shares, Kabu mini, and one share.
One stock is enough to start with. After placing your order, check the following three things.
| Things to check | Points to see |
|---|---|
| Execution price | Is there a discrepancy from the stock price you were looking at |
| Commission/spread | What is the real cost |
| Delivery/reflection timing | When are shares displayed as held |
Once you do this check, you will be much less anxious the next time you make a purchase.
How to use it for beginners
Pattern 1: Learn about individual stocks with a focus on investment trusts
If you want to invest 10,000 yen a month, you can divide it up as follows.
| Usage | Amount example | Purpose |
|---|---|---|
| Index investment trust | 5,000 yen | Widely diversified |
| Shares less than one unit | 5,000 yen | Get used to the price movements of individual stocks |
This is an example and is not an optimal solution. If you're worried about individual stocks, you can just buy investment trusts, or if you've already invested in investment trusts, you can buy just one stock for study purposes.
Pattern 2: Learn the dividend system
If a company pays dividends, you may receive a dividend based on the number of shares you own, even if it's just one share.
If you look at the dividend right date, ex-dividend, deposit date, and after-tax amount, you can get a good idea of the practicalities of stock investment. Rather than choosing a stock based on its dividend yield alone, you want to check whether the dividend is supported by its profits.
Pattern 3: Increase purchases little by little toward 100 shares
If you want to own a unit of stock that includes shareholder benefits and voting rights in the future, you can also buy one more share every month.
However, it is difficult to practice if you repeatedly buy stock prices in a hurry because they have gone up, and sell them out of fear when they have gone down. If you write down your reasons for buying something, you can look back on it later.
Common mistakes
Buy only popular stocks
Stocks that are popular on social media may already be bought based on expectations. If it's just one stock, the amount of loss may seem small, but if you only buy stocks with wild price movements, it's easier to rely on short-term price movements than to practice investing.
Don't look at commissions or spreads
For small investments, the cost tends to be large.
Even if it says "free", I would like to check which account, which order method, and which trading time the transaction is about. Spreads in real-time trading are especially easy to overlook.
Buy only one share for preferential purposes
Many companies make shareholder benefits conditional on holding a single unit of stock, such as 100 or more shares. There are cases where holding just one share is eligible, but it is difficult to recommend buying based on that assumption.
If you are aiming for special benefits, check the conditions on the official IR or shareholder benefits page. View the vesting month, number of shares held, and conditions for continued holding.
summary
Mini stocks and shares less than one unit are a convenient way to learn about Japanese stocks with a small amount of money.
Since you can buy from 1 share, it is easy to access stocks that are financially heavy with 100 shares. It is also easy to diversify, and some securities companies allow you to combine it with the NISA growth investment limit.
However, just because it's small doesn't mean it's safe. Stock prices may fall and dividends may be reduced. You also need to check order timing, commissions, spreads, preferential conditions, and how losses are handled under NISA.
The first purpose is to get used to the investment structure rather than increasing it significantly. Buy a share and follow prices, dividends, earnings, and news. From there, you can gradually find the investment amount and number of stocks that suit you.
source
- Japan Exchange Group "Becoming a shareholder"
- Financial Services Agency "Know NISA"
- [SBI Securities "Can I buy and sell shares constituting less than one unit? Please tell me the fees and precautions"] (https://faq.sbisec.co.jp/answer/5f17d6e68c7981001102a0c0/)
- SBI Securities "Domestic Stock Brokerage Fee"
- Rakuten Securities “Kabu Mini® (fractional share trading) commission”
- Rakuten Securities “Kabu Mini® (Stocks less than one unit trading)”
- Monex Securities “One share (shares less than one unit)”