Conversely, a market cap-weighted index fund allocates proportionately, so the larger companies’ stock or bonds make up a higher share of the index and the smaller companies’ stock or bonds comprise a smaller amount. Why does equal- versus market cap-weighted matter? The market cap-weighted peer generated a cumulative return of 224.68% over the same timeframe, turning $10,000 into $33,360. But in the market cap-weighted index, its winners have generated significantly higher returns. Ultimately the choice between equal- or market cap-weighted funds depends on what you want to achieve.