Asset Building & NISA 2026

The first profit always wants to go straight in. Decide what stays in cash before NISA.

Build the position you can withdraw from before the one that grows.

15 Mar

Income tax due, the following year

Next year

When sold NISA headroom returns

T+2

Settlement: 3rd business day from trade

9 slides

The day the balance first showed four digits

2 / 9

¥3,200. ¥8,700. Nowhere near what the hours were worth.

And yet it is the first time something you built came back as an amount. What follows is almost always the same thought: leaving this idle is a waste.

💡 The first thing to build is not a position that grows, but one you can withdraw from

Tax leaves in cash, the following year

3 / 9

When	What happens	Source
1 Jan – 31 Dec 2026	The profit arises	—
16 Feb – 15 Mar 2027	Income tax return filed and paid	NTA No.2024
Fiscal 2027	Resident tax based on 2026 income	MIC

💡 The income-based portion of resident tax is 10% (4% prefectural, 6% municipal), calculated on the prior year's income (MIC)

Inside NISA, a loss never happened

4 / 9

A loss on instruments acquired in a tax-exempt account is deemed not to exist.

It cannot be offset against dividends or gains in a specific or general account, and it cannot be carried forward. (Source: National Tax Agency, No.1535)

⚠️ Tax exemption cuts both ways. Money with a fixed outgoing date has little reason to sit somewhere that moves

Selling is not same-day cash

5 / 9

📅

Listed instruments: delivery on the third business day counted from the trade date (T+2, in force for trades from 16 July 2019 — Japan Exchange Group)

🏦

Then: withdrawing from the brokerage account to your bank adds another step

📄

Investment trusts: terms are set per fund. Check the prospectus or distributor once

💡 "I can sell if I need to" is true. It is just not true today

Headroom returns on a yearly cycle

6 / 9

Item	Detail (source: FSA)
Annual allowance	¥1.2m Tsumitate / ¥2.4m Growth (¥3.6m combined)
Lifetime limit	¥18m, of which Growth is capped at ¥12m
Holding period	Indefinite under the 2024 NISA
After selling	Book value restored from the following year onward

💡 Book value, not market value — and next year, not this one. An indefinite holding period means less reason to rush

Three buckets

7 / 9

1️⃣

Tax bucket: a set share of every payout moves here and stays. The share depends on your own classification and rate

2️⃣

Living bucket: cash that keeps life running if income stops. Do not borrow someone else's "x months"

3️⃣

Investment bucket: what remains once 1 and 2 are filled. This is where NISA belongs

✅ Start at 3 and buckets 1 and 2 never fill. Side income is not level month to month

Common move / what to do instead

8 / 9

Common move	What to do instead
Auto-route every payout into the investment	Move the tax share to a separate account first
Treat filling the allowance as the goal	Fix the cash first; use the allowance with what's left
Assume you can just sell if it runs short	Plan around settlement days and yearly headroom
Assume a loss offsets gains elsewhere	Size positions on the basis that it offsets nothing

💡 Every line looks like it shrinks the upside. It is preparation for not having to sell

One thing to do today

Add up your side income so far this year

Estimate the share of it that belongs to tax, under your own circumstances

Move that amount to a separate account

What remains is money you can spend without touching the tax payment. NISA comes after

※

General information only, not individual investment advice. Confirm tax questions with your local tax office or a licensed tax accountant. The decision is yours

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