Market Cap Weight Calculator
Build market capitalization weighted portfolios
Portfolio Assets
Market Cap Weighted Allocation
Concentration Analysis
Top 3 Holdings
0%
HHI Index
0
Portfolio Characteristics
Market Cap Weight Breakdown
| Rank | Asset | Market Cap ($B) | Weight | Cumulative | Size Category |
|---|
When to Use Market Cap Weighting
Index Fund Replication
Want to replicate S&P 500? Use market cap weighting. Apple gets 7%, Microsoft 6%, small stocks 0.01%. Matches index performance exactly. Most ETFs use this method.
Passive Investing
Set it and forget it. Market cap weighting is self-rebalancing. Winners automatically get larger weights, losers get smaller. No manual rebalancing needed. Perfect for passive strategies.
Low Cost Portfolios
Market cap weighting has lowest turnover. No frequent rebalancing = lower trading costs and taxes. Expense ratios as low as 0.03% for index funds. Cost efficiency matters for long-term returns.
Market Consensus
Market cap reflects collective wisdom of all investors. Apple worth $3T because millions of investors agree. Market cap weighting follows this consensus. No need to second-guess the market.
Broad Market Exposure
Want exposure to entire market? Market cap weighting gives you that. Large caps dominate because they're large. Small caps get small weights because they're small. Natural market representation.
Crypto Market Tracking
Total crypto market cap: $2T. Bitcoin $1.2T = 60% weight. Ethereum $400B = 20% weight. Others get remaining 20%. Tracks overall crypto market movements naturally.
Frequently Asked Questions
What is market cap weighting?
Allocates based on company size. Larger companies get bigger allocations. Apple $3T gets 7% of S&P 500, small company $1B gets 0.02%. Weight = Company Market Cap / Total Market Cap.
How to calculate weights?
Weight = (Individual Market Cap / Total Market Cap) × 100%. Example: Apple $3T, total $6.6T. Apple weight = ($3T / $6.6T) × 100% = 45.5%. This calculator does math automatically.
Benefits of market cap weighting?
Reflects market consensus. Self-rebalancing. Low turnover and costs. Matches market performance. Used by S&P 500, NASDAQ. Passive, efficient approach.
Drawbacks?
Concentration risk—few large companies dominate. Apple + Microsoft = 13% of S&P 500. Momentum bias—overweights expensive stocks. Can create bubbles when large caps overvalued.
Market cap vs equal weight?
Market cap: Apple 7%, small stocks 0.01%. Equal weight: All same %. Market cap has lower volatility, matches market. Equal weight has better diversification, historically outperformed by 1-2%.
When to use?
Best for: Index investing, passive strategies, matching market returns, low-cost portfolios, tax efficiency. Use when you want broad market exposure without active management. Most ETFs use this.
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