Founded in 1994 as an online bookstore, Amazon.com Inc. (NASDAQ: AMZN) has become the largest Internet-based retailer in the world. The company has also branched out into cloud computing, electronics, and content distribution, and it has begun testing drone delivery in certain areas.

Amazon's stock has become notable for its extreme overvaluation according to traditional valuation metrics. One of the main reasons for Amazon's lack of profitability is its continued dedication to expansion by reinvesting much of its earnings and cash flow back into the business. This high-growth strategy has made its stock popular among both individuals and mutual funds that employ a higher-risk investing approach. 

Here are the top five mutual fund holders of Amazon who collectively own 6.9% of the company, as of October 25, 2018.

The Vanguard Total Stock Market Index Fund (VTSMX)

The Vanguard Total Stock Market Index Fund (VTSMX) is one of the largest mutual funds and provides broad stock market exposure. The fund passively manages $756.6 billion in total assets. As of October 2018, VTSMX owns 10.5 million Amazon shares, which accounts for 2.78% of the funds' total assets and 2.16% of Amazon's total shares held. The fund has an expense ratio of 0.14% and a minimum investment of $3,000.

The Vanguard 500 Index INV (VFINX)

Offering exposure to some of the largest U.S. companies, the Vanguard 500 Index (VFINX) is the second-largest mutual fund holder in Amazon, with over 7.6 million shares to its name, or 1.56% of the company, as of October 2018. VFINX's assets total $459.3 billion, with 3.32% of those assets invested in the Amazon stock. The fund has an expense ratio of 0.14% and requires a minimum investment of $3,000. 

The American Funds Growth Fund of America (AGTHX)

The American Funds Growth Fund of America (AGTHX) invests at least 65% of its $176.4-billion portfolio in common stocks and provides growth through broad market exposure. As of October 2018, the mutual fund owns 5.9 million shares of Amazon. The fund's investment in Amazon accounts for 1.21% of the company and 6.18% of the fund's total assets. AGTHX has an expense ratio of 0.64% and a minimum investment of $250.

The Fidelity Contrafund (FCNTX)

The Fidelity Contrafund (FCNTX) is the fourth-largest Amazon major fund shareholder, with 4.9 million shares, or just over 1% of the company, as of October 25, 2018. The fund holds total assets exceeding $134.9 billion as of October 2018. It seeks to invest when a stock's price doesn't fully reflect its company's intrinsic value. As such, it focuses on large-cap stocks that the fund's managers feel are unloved or underappreciated by Wall Street. The fund has 7.36% of its total assets invested in Amazon. FCNTX has an expense ratio of 0.74% and a minimum investment of $2,500.

The SPDR S&P 500 ETF (SPY)

The SPDR S&P 500 ETF (SPY) is the first ever ETF introduced in the U.S. public market and remains one of the most popular to this day. As of October 2018, SPY is the fifth-largest Amazon holder with 4.6 million shares of the company. SPY's investment in Amazon represents 3.32% of the fund's $71.88-billion portfolio and 0.95% of Amazon's total shares. SPY has an expense ratio of 0.09%.