Tool 05 / allocation · local-first

投资组合再平衡器Portfolio Rebalancer

See what is actually out of balance, decide whether it deserves a trade, and compare the cost of precision with the cost of doing nothing.

state · living made with · JavaScript quotes · manual until refreshed storage · this browser

Portfolio now

What you own

Portfolio value

—

base currency · USD

Invested

—

Cash

—

Portfolio drift

—

½ Σ |当前 − 目标|½ Σ |current − target|

Largest position

—

Inputs

Holdings & targets

Targets may be exact or bands. A band lets a position drift without creating pointless trades.

target · —

This workspace starts empty. Add an asset or load the clearly marked demo; nothing shown here is a published miaolay holding.

Asset	Name	类型Type	Class	Qty	Price	CCY	Cost	Value	Weight	Target	Band min	Band max	Drift	Lock

Cash balance

Cash target %

Base currency

Price status

manual values

Cost is optional cost per share. It is used only to estimate embedded gain on proposed sells; this page does not calculate tax liability.

Structure

Current vs target

The dark bar is current weight. The thin line is the target. Positions inside their allowed band can be left alone.

当前Currenttarget

Drift map

Decision

Rebalance only as much as needed

Exactness is optional. Lock positions, protect cash, ignore tiny trades, or use new contributions to dilute an overweight position naturally.

respect target bands

New money

Keep cash ≥

Ignore trades below

Minimum-trades tolerance

fractional shares prefer buys when a sell embeds gains

Estimated commission / trade

Max number of trades (minimum mode)

Maximum single position %

Soft rebalance threshold %

Recommended trades

After

Drift

—

Trades

—

Cash left

—

Estimated realized gain

—

rough, before tax

No calculation yet.

Trade-off

Rebalance frontier

How much allocation accuracy does each additional trade buy? The highlighted row is the first point that reaches your drift tolerance.

Trades vs remaining drift

Practical point

—

This is not an optimizer of expected return. It only measures how much target-allocation error remains after taking the largest mechanical rebalance actions first.

No-sell path

Can time fix the overweight?

For a position you do not want to sell, calculate the new capital required to dilute it to a target weight while its price stays unchanged.

Position

Desired weight %

Monthly contribution

Annual contribution growth %

NEW CAPITAL REQUIRED

—

This isolates dilution only. Market movement will change the result.

Future cash flow

Contribution routing

Project how recurring contributions can repair drift without selling. Prices are held constant so the result isolates the effect of cash flow.

Monthly contribution

Projection months

Annual contribution growth %

Keep cash ≥

Each month, investable cash is routed toward the largest target-value gaps. Positions are never sold in this simulation.

Projected drift

—

Inside all bands

—

first projected month

Cash after horizon

—

NEXT CONTRIBUTION ROUTING

Risk

Concentration you can explain

No black-box score. Each number has a direct interpretation and can be reproduced from the weights above.

Top 3 concentration

—

share of total portfolio

HHI

—

Σ weight², incl. cash

Effective positions

—

1 / HHI

Largest −50%

—

direct portfolio impact

Class risk budget

Budget readout

—

Class ceilings are user-defined policy limits, not statistically estimated risk. They are useful when your investment rule is expressed as “growth + speculative must stay below X%.”

Stress assumptions

Scenario result

—

CONTRIBUTION BY CLASS

Data

Live data is optional

A quote is an input, not a recommendation. Manual prices remain first-class so the calculator still works when every API is unavailable.

Finnhub

free key

Primary option for US equity quotes. User key stays in this browser.

Twelve Data

free key

Fallback for equities and ETFs; useful when you want broader symbol coverage.

Alpha Vantage

free key · EOD fallback

Low-frequency fallback. Free GLOBAL_QUOTE should not be presented as live US pricing.

Frankfurter

no key

FX conversion. Open CORS, no daily/monthly quota, reference rates rather than trading quotes.

CoinGecko

演示密钥Demo key

Optional crypto quotes. Common symbols are mapped locally to CoinGecko IDs.

手动Manual

always available

Never block calculation because a provider is down, rate-limited, or missing a symbol.

边界Boundary

A calculator is not a portfolio manager

Holdings, targets, API keys, and saved states are kept in this browser. Quote requests go directly from your browser to the provider you enable. The page can calculate allocation, drift, concentration, mechanical rebalancing, and simple shocks. It cannot know your tax jurisdiction, liquidity needs, execution quality, future returns, or whether a target allocation is appropriate.

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