There is no doubt about it: small-cap ETFs and stocks are easily outperforming their large-cap rivals this year. As of Sept. 14, the iShares Russell 2000 ETF (NYSEARCA:IWM) is up 13.1% year-to-date while the large-cap S&P 500 is higher by 9.9%.

On a risk-adjusted basis, some small-cap stocks and exchange-traded funds (ETFs) look even better. Annualized volatility on IWM and the S&P 500 is exactly the same to this point in the year. Usually, small-cap stocks are more volatile than their large-cap counterparts. Data suggest the small-cap premium to larger stocks is exceptional by historical standards.

“This has driven the S&P 600 (TR) 8.4% higher than the S&P 500 (TR) (year-to-date through Aug.31, 2018,) measuring the 5th biggest small cap premium in history since 1995, and is the biggest since 2008, when it reached 10.2%,” said S&P Dow Jones Indices.

Here are 7 small-cap ETFs that are in the midst of impressive year-to-date surges with the potential to add to those gains in the months ahead.

Small-Cap ETFs to Buy: iShares Core S&P Small-Cap ETF (IJR)

Expense ratio: 0.07% per year, or $7 on a $10,000 investment.

The iShares Core S&P Small-Cap ETF (NYSEARCA:IJR) is one of the largest small-cap ETFs trading in U.S. and is rival to funds tracking the Russell 2000 Index because IJR targets the S&P SmallCap 600 Index, a competing benchmark to the Russell 2000.

IJR “tracks the less popular S&P SmallCap 600 Index and uses buffering rules to mitigate turnover when it doesn’t materially affect the portfolio’s composition. This is a well-diversified small-cap index that accurately represents its peers’ opportunity set,” said Morningstar in a recent note.

IJR is ideal for investors that want broad-based small-cap exposure for a nominal fee. This ETF holds over 600 small-cap stocks and charges just 0.07% per year, making it one of the most cost-effective options in this category. IJR is up more than 17% year-to-date.

Small-Cap ETFs to Buy: Invesco S&P SmallCap Health Care ETF (PSCH)

Expense ratio: 0.29% per year, or $29 on a $10,000 investment.

When it comes to small-cap ETFs, investors often favor diversified funds such as the aforementioned mentioned IJR and IWM, but there are advantages to getting tactical at the sector level with small-cap funds. Invesco, the fourth-largest U.S. ETF issuer, is the dominant purveyor of small-cap sector ETFs, all of which track sector-level offshoots of the S&P SmallCap 600.

One of this year’s best-performing small-cap ETFs, regardless of investment objective, is the Invesco S&P SmallCap Health Care ETF(NASDAQ:PSCH). PSCH is up 45.5% year-to-date, or more than triple the returns of the large-cap S&P 500 Health Care Index. The $1.36 billion PSCH provides exposure to companies “engaged in the business of providing healthcare-related products and services, including biotechnology, pharmaceuticals, medical technology and supplies, and facilities,” according to the issuer.

Three industries — healthcare equipment makers, services providers and biotechnology — are the primary drivers of PSCH’s returns. Those groups combine for over three-quarters of the fund’s weight.

Small-Cap ETFs to Buy: SPDR Portfolio Small Cap ETF (SPSM)

Expense ratio: 0.05% per year, or $5 on a $10,000 investment.

As was noted with IJR, there are plenty of cheap small-cap ETFs on the market today, but there are just two with expense ratios of less than 0.07%. The SPDR Portfolio Small Cap ETF (NYSEARCA:SPSM)is one of those two funds.

SPSM targets the SSGA Small Cap Index and is home to just over 2,000 stocks, giving this small-cap ETF the feel of a fund that tracks the Rusell 2000 Index. Year-to-date, SPSM’s returns have been almost inline with those of the Russell 2000. Over longer holding periods, SPSM’s scant fee will work in favor of thrifty investors looking to retain more of their invested capital.

This small-cap ETF devotes nearly a third of its weight to technology and financial services stocks, sector weights that are comparable to those found in the Russell 2000.

Small-Cap ETFs to Buy: Schwab Fundamental U.S. Small Company Index ETF (FNDA)

Expense ratio: 0.25% per year, or $25 on a $10,000 investment.

The Schwab Fundamental U.S. Small Company Index ETF(NYSEARCA:FNDA) is a small-cap ETF worth considering by conservative investors looking for an alternative to the cap-weighted methodology that is common in the small-cap fund universe. FNDA is not an explicit value fund, but the fundamentals it uses in its weighting scheme give this Schwab product a value feel.

“This fund offers broad exposure to small-cap U.S. stocks but weights them on fundamental measures of size, including sales (adjusted for leverage), retained operating cash flow, and dividends plus share buybacks, rather than market cap,” according to Morningstar. “This causes the fund to tilt toward stocks trading at low multiples of these metrics and away from stocks trading at higher valuations. However, it does not exclude growth stocks.”

Over the long-term, FNDA has been a steady small-cap bet.

“From its inception in August 2013 through August 2018, the fund outpaced the Russell 2000 Value Index by 1.39 percentage points annualized,” said Morningstar. “However, it slightly lagged the Russell 2000 Index by 7 basis points annually, owing to a stretch of underperformance in the past year, which stemmed partially from its underweighting of the healthcare sector.”

Small-Cap ETFs to Buy: Invesco S&P SmallCap Quality ETF (XSHQ)

Expense ratio: 0.29% per year, or $29 on a $10,000 investment.

Investors looking for funds that are topping diversified rivals may want to give a nod to the Invesco S&P SmallCap Quality ETF(CBOE:XSHQ), which is up more than 15% this year. That is a sign the quality factor is more than applicable to small-cap stocks.

XSHQ, which is nearly a year and a half old, targets the S&P SmallCap 600 Quality Index, a collection of quality fare from the broader S&P SmallCap 600.

“The Index is composed of 120 securities in the S&P SmallCap 600 Index that have the highest quality score, which is calculated based on the average of three fundamental measures: return on equity, accruals ratio and financial leverage ratio,” notes Invesco.

Financial services and consume discretionary names combine for over 40% of XSHQ’s weight.

Small-Cap ETFs to Buy: JPMorgan Diversified Return U.S. Small Cap Equity ETF (JPSE)

Expense ratio: 0.29% per year, or $29 on a $10,000 investment.

Some small-cap ETFs, such as XSHQ, focus on a single investment factor. The JPMorgan Diversified Return U.S. Small Cap Equity ETF (NYSEARCA:JPSE) shatters that mold by employing several factors in its weighting methodology.

JPSE “utilizes a rules-based approach that combines risk-based portfolio construction with multi-factor security selection, including value, quality and momentum factors,” according to JPMorgan Asset Management.

JPSE’s year-to-date performance is more than admirable, particularly when considering its exposure to the lagging low volatility and value factors. This small-cap ETF is up 12.20% and resides less than 1.10% below its all-time high.

Even more impressive is that JPSE is generating those returns with a 22.60% weight to the conservative (and struggling) consumer goods space. Consumer discretionary and industrial stocks combine for 26.60% of this small-cap ETF’s roster.

Small-Cap ETFs to Buy: SPDR SSGA US Small Cap Low Volatility Index ETF (SMLV)

Expense ratio: 0.12% per year, or $12 on a $10,000 investment.

Historically, small-cap stocks are more volatile than larger fare, but some small-cap ETFs attempt to solve or reduce the volatility associated with smaller stocks. The SPDR SSGA US Small Cap Low Volatility Index ETF(NYSEARCA:SMLV), an overlooked small-cap ETF, is one of those funds.

This small-cap ETF, which is five and a half years old, targets the SSGA US Small Cap Low Volatility Index. That index holds ranks stocks by low standard deviation over a specific time frame. When small-cap stocks are rallying, as is the case this year, the introduction of the low volatility factor can keep a lid on returns as highlighted by SMLV’s year-to-date returns of 8.42%. Then again, low volatility funds are designed to be less bad when stocks fall, not to capture all of a bull market’s upside.

Some low volatility funds can be top heavy at the sector level and that applies to SMLV. This small-cap ETF devotes nearly 47% of its combined weight to financial services and real estate stocks. Additionally, this small-cap ETF is one of the least expensive low volatility funds on the market, particularly among small-cap fare.

Todd Shriber does not own any of the aforementioned securities.