Rebalance

Disclaimer: This tool is for educational and informational purposes only and is not intended as financial or investment advice. I am not a financial advisor. This software is provided "as-is" with no warranties of accuracy or completeness. It may contain bugs or calculation errors. Do not rely on it for actual investment decisions. Consult a qualified financial professional before making any trades. I accept no liability for any losses or damages arising from use of this tool.

A portfolio rebalancing tool that runs in both the terminal and the browser from a single codebase, powered by ink-web. Read the blog post.

What it does

Import your Schwab brokerage holdings (CSV paste or drag-and-drop), set target allocation percentages, and generate the exact trades needed to rebalance — all without sending your data to a server.

The wizard walks you through four steps:

1. Import — Paste a CSV, drag-and-drop a file, or pick a demo portfolio
2. Review — Browse your holdings across multiple dimensions (symbol, account, country, asset class, tax status, provider, owner)
3. Targets — Set target percentages for each symbol with real-time validation
4. Trades — Generate trades using one of two strategies, then export as CSV

Rebalancing strategies

• Minimize Trades — Makes the smallest changes needed to hit your targets. Best for taxable accounts or frequent rebalancing.
• Consolidate — Moves each symbol into as few accounts as possible. Creates more trades but simplifies your portfolio structure.

Both strategies use a largest-remainder algorithm to convert dollar targets into whole shares while minimizing rounding error and respecting per-account budget constraints.

How it works

The UI is built with Ink (React for the terminal). ink-web bridges Ink to the browser by polyfilling Node.js APIs and connecting Ink's renderer to xterm.js. The same React components render natively in both environments — no code duplication.

In the browser, portfolio data is stored locally using the Origin Private File System (OPFS). In the terminal, it uses the local filesystem. A StorageAdapter interface abstracts the difference.

Install

npm install -g @cjroth/rebalance

Usage

Browser

npm run dev

Opens at http://localhost:1420. Drag and drop a CSV file or paste one in. Everything runs client-side.

Terminal

bun src/cli.ts              # full wizard
bun src/cli.ts import       # jump to a specific step
bun src/cli.ts review
bun src/cli.ts targets
bun src/cli.ts trades
bun src/cli.ts ./my-data    # custom data directory (default: ./portfolio-data)

CSV format

The universal CSV format uses #section headers:

#holdings
account,symbol,shares
401k,VTI,100
Roth IRA,VXUS,50

#symbols
name,price,countries,assets,beta
VTI,250.00,us:1.0,equity:1.0,1.0
VXUS,60.00,international:1.0,equity:1.0,1.1

#accounts
name,tax_status,provider,owner
401k,traditional,fidelity,sam
Roth IRA,roth,fidelity,sam

#targets
symbol,percent
VTI,60
VXUS,40

Only #holdings is required. Charles Schwab CSV exports are also auto-detected and parsed.

As a library

The rebalancing logic is published as @cjroth/rebalance and can be used programmatically:

import { calculateRebalanceMinTrades, calculateRebalance, convertToWholeShares } from '@cjroth/rebalance'

There's also a Next.js-compatible export for embedding the wizard in a web app:

import { Wizard } from '@cjroth/rebalance/next'

Tech stack

• React 19 + Ink 6 — shared UI across terminal and browser
• ink-web — the bridge that makes it work in both environments
• Vite 7 — dev server and bundler
• Bun — runtime for the CLI
• Zod 4 — schema validation
• xterm.js — terminal emulator in the browser
• TypeScript — strict mode throughout