Many 401(k) retirement accounts are loaded down with mutual funds, but there are better options. Exchange-traded funds have a more transparent fee structure, they can be traded in a more granular way, and they’re typically every bit as good as mutual funds with less overhead.

If you’re an investor who wants to make the most of their 401(k), consider these 7 ETFs with extremely low expense ratios as of December 30, 2016. (See also: Pay Attention To Your Fund’s Expense Ratio.)

Vanguard Total Stock Market (SPY)

  • Issuer: State Street SPDR
  • Average Volume: 90,900,000 shares
  • 2016 Performance: 12%
  • Expense Ratio: 0.09%

The S&P 500 has long been seen as the bellwether index for the American stock market. S&P 500 index funds have been a favorite retirement holding for decades. SPY just repackages this old standby, with lower expenses and less paperwork than traditional index funds. This ETF is an excellent addition to any 401(k) portfolio, and institutional investors will tell you that S&P 500 index funds should play a role in most retirement accounts.

Vanguard Total Stock Market (VTI)

  • Issuer: Vanguard
  • Average Volume: 2,700,000 shares
  • 2016 Performance: 12.81%
  • Expense Ratio: 0.05%

Vanguard's Total Stock Market ETF is an alternative to other market index funds. VTI gives investors exposure across the entire Nasdaq and NYSE, with securities from every sector and segment. This ETF has a rock-bottom expense ratio, a massive amount of assets under management, and a good track record with solid returns. Investors looking for a broad index to include in their 401(k) could do a lot worse.

iShares Core U.S. Aggregate Bond (AGG)

  • Issuer: iShares
  • Average Volume: 3,000,000 shares
  • 2016 Performance: 1.42%
  • Expense Ratio: 0.05%

The long-term stability of the bond market makes AGG an excellent choice for young investors who need rock-solid assets in their 401(k). AGG gives investors a stake in the bond market without requiring a set amount of time for maturation. That kind of flexibility, along with steady performance, makes this ETF a good choice for a 401(k), despite the relatively low returns.

iShares MSCI Emerging Markets (EEM)

  • Issuer: iShares
  • Average Volume: 65,900,000
  • 2016 Performance: 10.86%
  • Expense Ratio: 0.67%

Emerging markets are exciting because they’re volatile, which isn’t always the best trait for a retirement investment. But the iShares MSCI Emerging Markets ETF is a good way to add a controlled amount of volatility to your retirement fund. The key is to be judicious, and not overexpose your retirement to emerging markets without anchoring your 401(k) in bonds and index funds. That said, EEM delivered above-average performance in 2016, and emerging markets like China and India are growing in proportion to the rest of the global economy.

Vanguard Value (VTV)

  • Issuer: Vanguard
  • Average Volume: 1,300,000 shares
  • 2016 Performance: 17.10%
  • Expense Ratio: 0.09%

VTV gives investors exposure to a range of large-cap securities, like Microsoft, ExxonMobil, Johnson & Johnson, and Berkshire Hathaway. As a result, this fund has returned over 100% over the past 5 years. Adding an ETF like Vanguard Value to your 401(k) is a great way to diversify away from index funds while still keeping your risk relatively low.

iShares Russell 2000 (IWM)

  • Issuer: iShares
  • Average Volume: 32,300,000 shares
  • 2016 Performance: 21.59%
  • Expense Ratio: 0.20%

In a way, the Russell 2000 index is a counterpart to the S&P 500. Instead of following 500 blue chips, the Russell indexes 2,000 small-cap securities. The iShares Russell 2000 ETF is a great addition to your 401(k) if you feel like most of the growth in the American economy over the next 20 years is going to come from smaller businesses. IWM gives investors a share of the Russell index with a relatively low expense ratio, which makes it uniquely suited for long-term investing.

iShares iBoxx High Yield Corporate Bond (HYG)

  • Issuer: iShares
  • Average Volume: 12,500,000
  • 2016 Performance: 10.26%
  • Expense Ratio: 0.50%

Corporate bonds can be a good alternative to treasury notes, as they offer investors higher returns on secured debt. The iShares iBoxx High Yield Corporate Bond ETF focuses on corporations with a BB bond rating, mixing in a few AAA bonds with some that are rated B and lower. On the whole, HYG has proven to offer steady returns – 26.09% over 5 years – with modest overhead. Adding HYG to your 401(k) is a good way to mix some corporate notes in with your government bonds.

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