So what does all this mean for your portfolio? Well, you probably don't have to worry as much about your value funds getting too big. But keep an eye out for sluggish risk-adjusted performance from your fast-trading growth funds as their asset bases rise.
And if you want to be proactive, keep an eye out for strategy changes. If you bought a fund to fit a small-growth niche in your portfolio, you might not be happy if it starts buying midsize or even large-cap stocks. A fund with a big cash stake can throw off your own asset-allocation decisions. Even if a growing fund is thriving, asset growth may still mean problems.