NISA Account Tracker

Track a Japanese NISA account: import purchase history exported from the SBI Securities website, fetch daily fund NAV from the Fund Library, and view on a local web dashboard the current value, historical value/profit graph, NISA limit usage, and a 10-year forecast. UI is available in Japanese and English.

Files

• input.csv — purchase history exported from SBI Securities (see below)
• db.py — SQLite storage, CSV import, valuation, NISA limit usage, forecast
• fetch.py — downloads daily NAV from toushin-lib.fwg.ne.jp into the DB
• app.py — Flask web app
• nisa.db — SQLite database (created on first run; delete to start over)

Export purchases from SBI Securities

SBI証券 のマイページ → 取引・投信 → 「取引履歴」から絞り込んでCSVダウンロードします。 The exported file should have these columns, in this order:

約定日,銘柄,銘柄コード,市場,取引,期限,預り,課税,約定数量,約定単価,手数料/諸経費等,税額,受渡日

Save it as input.csv in this folder (replace the bundled sample).

Notes:

• Dates use M/D/Y (e.g. 8/4/2026 = 2026-08-04). The import assumes this format; it is NOT D/M/Y.
• 銘柄 is matched by normalizing spaces and case, so you can keep the full-width names as exported (ｅＭＡＸＩＳ　Ｓｌｉｍ　米国株式（Ｓ＆Ｐ５００）).
• 約定単価 is the NAV per 10,000 units (万口), so invested cost is computed as 約定数量 × 約定単価 ÷ 10,000.
• Rows are deduplicated on (date, fund, quantity, unit price, account); re-importing the same file is safe.

Each fund needs an entry in db.FUNDS (ISIN + Fund Library code). The bundled eMAXIS Slim funds are already mapped; add new ones there. The CSV import explains which names could not be matched.

Setup

python3 -m venv .venv
.venv/bin/pip install -e .

This installs Flask + requests into the venv (requirements live in pyproject.toml) and provides the nisa-app / nisa-fetch commands.

Run

.venv/bin/python app.py

Opens at http://localhost:5000.

On startup the app imports input.csv (only when the DB is empty), refreshes prices, then keeps refreshing in the background every 24h. Use the 「価格更新」 button to refresh manually.

Using the dashboard

• Cards show total invested, current value, and profit (¥ and %, green/red).
• Value graph plots total value and total profit with 1Y / 5Y / All buttons to set the time range (no reload, instant).
• Tsumitate simulation (stacked chart): cumulative invested over time plus a 10-year projection at the monthly amounts and assumed annual return from the forecast settings; projected profit is stacked on top of invested.
• NISA limits show yearly usage for つみたて/成長/combined vs. the new-NISA caps, including a forecast of when you would exceed them.
• Forecast (10 years) shows projected value, contributions, and profit from the settings below it.
• Forecast settings (monthly つみたて amount, monthly 成長 amount, assumed annual return) are editable on the page and stored in the DB.
• Buy a fund (+ button or POST /api/buy with {"date":"YYYY-MM-DD","amount":100000,"fund":"<ISIN>"}) adds a purchase using the fund's NAV on or before that date; duplicates are rejected. Costs count against NISA limits by account type.

CLI tools

• Import / refresh manually:

  .venv/bin/python db.py -i input.csv      # import purchases
  .venv/bin/python fetch.py                # fetch latest NAV for all funds

• Or use the installed commands: nisa-app / nisa-fetch.

NISA limits (new NISA)

• Tsumitate yearly: ¥1,200,000
• Growth yearly: ¥2,400,000
• Combined yearly: ¥3,600,000
• Lifetime: ¥18,000,000 (growth: ¥12,000,000)

Constants live in db.py.