These 4 Vanguard ETFs Are All You Need for a Well-Rounded Stock Portfolio

There are many misconceptions about investing, and a common one is that it's difficult. Are there many moving parts that are confusing, even for those who study this for a living? Absolutely. Does it have to be complicated or require "advanced knowledge"? Not at all.

One way to simplify investing is to use exchange-traded funds (ETFs). Seasoned investors preach the importance of a well-rounded and diversified portfolio, and using ETFs is arguably the easiest way to accomplish this goal. There's no need to invest in dozens (or hundreds) of individual stocks if you don't want to do so. A few ETFs can do the trick.

Following are four Vanguard ETFs that can give you a well-rounded portfolio you can lean on for the long haul.

If you ask me, no single investment serves as a better one-stop shop than an S&P 500 ETF. The Vanguard S&P 500 ETF (NYSEMKT: VOO) is my largest holding and likely will be for the remainder of my investing journey.

The S&P 500 index tracks 500 of the largest U.S. companies on the market, so investing in this ETF exposes you to some of the world's most accomplished and promising companies. It contains businesses from all the major sectors, many of which are industry leaders. Here's how the ETF is broken down by sector (as of Sept. 30):

• Communication services: 8.9%

• Consumer discretionary: 10.1%

• Consumer staples: 5.9%

• Energy: 3.3%

• Financials: 12.9%

• Health care: 11.6%

• Industrials: 8.5%

• Information technology: 31.7%

• Materials: 2.2%

• Other: 0.1%

• Real estate: 2.3%

• Utilities: 2.5%

There's volatility with any stock or ETF on the market. However, this ETF generally has more long-term stability because it contains all large-cap companies better built to weather whatever storms come their way. Since it was created, it has averaged impressive annual returns.

If you're looking for a single ETF that can be the bulk of your portfolio, this is it.

The Vanguard Mid-Cap ETF (NYSEMKT: VO) contains just over 310 mid-sized companies. Typically, mid-cap companies have a market capitalization between $2 billion and $10 billion. Because of the size of the companies in this ETF, it can be the sweet spot between stability and growth.

On the one hand, mid-cap companies are small enough to be agile and take on new growth opportunities. On the other hand, companies that managed to hit this market size typically have sustainable business models.

This ETF also contains companies from all major sectors, but it's more diversified than the S&P 500. The top five represented sectors are industrials (21.1%), consumer discretionary (12.3%), financials (12.6%), technology (13.8%), and healthcare (9.2%).