Apple (AAPL) shares had a rough week, tumbling almost 6% and dragging down a number of popular exchange-traded funds (ETFs) that are heavily exposed to the world's most valuable company.

With a market capitalization of $2.79 trillion as of Friday's market close, Apple is the most valuable publicly-traded company in the world. That makes it the biggest component stock in the S&P 500 Index, and the biggest holding in many popular ETFs available to investors.

Apple accounts for more than 7% of the SPDR S&P 500 Trust (SPY), one of the most popular and widely-held ETFs that tracks the performance of the S&P 500, which fell roughly 1.3% this week. The Invesco QQQ Trust (QQQ), which tracks the tech-heavy Nasdaq 100, has about 11% of its portfolio invested in Apple shares. It fell roughly 1.5% this week.

Even more exposed is the iShares Russell 1000 Growth ETF (IWF), with a 12.1% weight toward AAPL. It was down about 1.3% this week.

Among all the major ETFs tracked by Morningstar, the Vanguard Information Technology ETF (VGT) is perhaps the most heavily exposed to Apple, with a massive 22.8% portfolio weight. VGT returns fell 2.33%, almost double the broader market's 1.3% decline.