Since debuting its first exchange-traded fund (ETF) in 2009, the Charles Schwab Corp. (SCHW) has become one of the biggest ETF providers in the industry, with total assets of more than $50 billion spread among more than 20 different funds. One of the primary drivers of Schwab's success has been its strategy of providing ultra-low-cost fund options. Over half of Schwab's ETFs have expense ratios of less than 0.1%.

Whereas the ETF industry has seen the creation of many narrowly focused niche funds, Schwab has largely prioritized broad-based index funds. Each of Schwab's five largest ETFs falls into this category.

Schwab U.S. Broad Market ETF

Benchmarked to the Dow Jones U.S. Broad Stock Market Index, the Schwab U.S. Broad Market ETF (SCHB) is designed to provide equity exposure across all sectors and market caps. The fund maintains holdings in roughly 2,000 of the largest publicly traded companies, and, with total assets under management (AUM) of $6.7 billion, as of Aug. 5, 2016. It is the largest ETF in Schwab's lineup.

The Broad Market ETF also has the distinction of being one of the cheapest funds available. Its expense ratio of 0.03% means that investors pay just $3 annually for every $10,000 invested.

Schwab U.S. Large Cap ETF

The objective of the Schwab U.S. Large Cap ETF (SCHX) is to replicate the performance of the large-cap portion of the domestic stock market. The fund's underlying index, the Dow Jones U.S. Large Cap Total Stock Market Index, captures the 750 largest companies according to market capitalization from the total stock market. The fund's smallest company has a market cap of roughly $200 million, as of July 31, 2016. While the fund is not a Standard & Poor's (S&P) 500 index fund, it has, historically, been highly correlated to the index.

The Large Cap ETF is Schwab's second-largest ETF with assets of $6 billion. Like the Broad Market ETF, it carries an ultra-low expense ratio of just 0.03%.

Schwab International Equity ETF

International funds belong in virtually all portfolios since they can provide above-average return potential, while helping to diversify and disseminate overall portfolio risk. The Schwab International Equity ETF (SCHF) can be a core international holding within a broader portfolio since it focuses on high-quality, large-cap and mid-cap stocks from outside the United States. As of July 31, 2016, the fund's largest country holdings were Japan, with 23% of assets; the United Kingdom, with 17% of assets; and France, garnering 8% of assets.

The International Equity ETF sports one of the lowest expense ratios in the foreign ETF space at 0.08%. It is Schwab's third-largest ETF with total assets of $6 billion.

Schwab U.S. Dividend Equity ETF

The Schwab U.S. Dividend Equity ETF (SCHD) has gained significant interest from investors due to its combination of ultra-low expenses and strong historical performance. The fund, which targets companies with long histories of strong and increasing dividends, has earned Morningstar's highest five-star rating. Its 30-day Securities and Exchange Commission (SEC) yield of 3.1% is well above the S&P 500's yield of 2%.

With total assets of $4.2 billion, the Dividend Equity ETF is Schwab's fourth-largest fund. It has an annual expense ratio of 0.07%.

Schwab U.S. Small Cap ETF

The Schwab U.S. Small Cap ETF (SCHA) seeks to capture the performance of the higher-risk, higher-return potential stocks from the domestic equity market. The fund's benchmark index, the Dow Jones U.S. Small Cap Total Stock Market Index, includes the stocks ranked 751-2,500 by market cap from the entire domestic stock market. While small-cap stocks can carry heightened risks, the fund's beta of 1.09, as of July 31, 2016, indicates that this fund is only slightly more risky than the S&P 500.

Another low-cost entry in the Schwab lineup with an expense ratio of 0.07%, the Small Cap ETF is the company's fifth-largest with assets of $3.7 billion.