optimalrebalancing.info

What It Is

Optimal Lazy Portfolio Rebalancing Calculator is a web-based “lazy rebalancing” portfolio calculator created by Albert Mao. It is designed for investors who follow a target asset allocation. The core idea is to buy only underweight assets when adding funds, avoiding sales; and sell only overweight assets when withdrawing funds, avoiding purchases. This helps keep the portfolio as close as possible to the target allocation while reducing transaction costs, taxable events, and operational effort. The page clearly states that the content is for informational purposes only and does not constitute legal or financial advice.

Core Features and Technical Implementation

The tool asks users to enter an additional investment amount, or a negative number for withdrawals. Users also enter asset names, target percentages, current values, and optionally share prices. The results table shows how much—or how many shares—of each asset should be bought or sold. It supports copy-pasting from spreadsheets, as long as the column order is correct. Algorithmically, the system uses “fractional deviation” to measure how far each asset is from its target allocation: when adding funds, it maximizes the minimum deviation across assets; when withdrawing, it minimizes the maximum deviation. The text also emphasizes that calculations use arbitrary-precision integer/rational-number libraries rather than relying on imprecise floating-point arithmetic.

Pricing, Deployment, and Security

The captured content does not show any subscription plans or paywall, only a Donate option, so it appears closer to a free, donation-supported tool. It is deployed as a web app, with the key calculations performed locally in the user’s browser. Privacy is a notable strength: the site states that it does not collect user information and that financial data is not transmitted. The JavaScript code is released under the GNU GPL, and the arbitrary-precision library it uses is MIT-licensed. However, there is no visible API, enterprise-grade audit information, compliance certification, or self-hosting installation guide.

Pros, Cons, and Best-Fit Users

Its strengths are a clear purpose, a low barrier to use, no account requirement, local data processing, and the ability to reduce the trading and tax friction associated with frequent rebalancing. Its limitations are also clear: it is not a full portfolio management SaaS product. There is no account system, team permissions, brokerage or market-data integrations, automatic syncing, reporting, or customer support SLA. Support appears to be limited to submitting comments, suggestions, and bugs via email. It is best suited to individual passive investors, DIY portfolio managers, or users who want to use the algorithm as a reference for spreadsheets or internal tools.

Access from China and Alternatives

The text does not make it possible to determine access conditions from mainland China, and payment methods are not disclosed. Since no login is required and calculations are local, the tool should be relatively easy to use if the webpage is accessible. However, users who need stable Chinese-language support, brokerage data syncing, or RMB asset management may want to consider building a spreadsheet model, using asset allocation tools provided by brokerages, or choosing other portfolio management platforms as alternatives.