If you had bought QQQ in 2017 with $10,000...

Invesco QQQ Trust is an exchange-traded fund that tracks the Nasdaq-100, an index of the largest non-financial companies listed on Nasdaq. Launched in March 1999, it is one of the most heavily traded ETFs in the world. Its composition is what distinguishes it from a broad-market fund: the index excludes financials entirely and is heavily weighted toward technology and communications, with the largest handful of holdings making up a substantial share of the fund. That concentration is the source of both its outperformance in technology-led markets and its deeper falls when those same names decline. QQQ charges an expense ratio and pays a distribution, neither of which a price-only comparison captures.

QQQ launched in March 1999, months before the dot-com peak, which makes its early history a useful warning: the fund lost roughly 80 percent from its 2000 high and did not regain that level for about fifteen years. The recovery came from a different set of companies than the ones that drove the bubble. Since then it has generally outpaced the S&P 500 in technology-led periods and fallen harder in downturns, including a decline of roughly a third in 2022. The underlying index is reconstituted annually, with occasional special rebalances when a few holdings grow large enough to distort the weighting - so the fund's exposure today is not the exposure it had a decade ago.

QQQ is the middle ground between a single stock and the whole market, and comparing its result with the S&P 500 over the same window shows exactly what the extra concentration bought - or cost. Starting years around 1999-2000 are the most instructive ones to run.