The top holdings of the PowerShares QQQ exchange-traded fund, an index fund tracking the Nasdaq 100, were Apple, Microsoft, Amazon, Alphabet Class A and C, Facebook, and Intel as of October 2015, according to data provided by Morningstar. PowerShares QQQ tracks the Nasdaq 100 index and thus holds all the index's component stocks. The index is made up of 100 of the largest non-financial companies traded on the Nasdaq exchange, weighted by market capitalization, according to Nasdaq.
Gilead Sciences, Cisco Systems, and Comcast rounded out PowerShares QQQ's top 10 holdings as of October 2015, according to Morningstar. Other well-known companies held by the index fund include Qualcomm, Starbucks, Priceline, Costco and Netflix.
The Nasdaq 100 includes many technology stocks because the exchange's all-electronic nature attracts companies in that sector, according to Market Realist. Furthermore, technology companies sometimes have their initial public offerings before they qualify for listing on the New York Stock Exchange. Technology companies represent over half of the value of the index and its tracking funds, with health care ranking as the second-largest component sector.
Since the index is weighted by market cap, the Nasdaq's largest companies represent a large proportion of Nasdaq index funds' holdings. In October 2015, Apple made up 13 percent of the PowerShares QQQ fund's value, while Microsoft accounted for 8 percent, according to Morningstar. The fund's top 10 holdings accounted for 49 percent of its value.