When it comes to ETFs, bigger is not always better.

While the oldest and largest ETF, the $283 billion AUM SPDR S&P 500 Trust, finished 2017 up an impressive 21.7 percent, its performance was eclipsed by many smaller, younger and less-well-known ETFs.

While ETF giants BlackRock, State Street, Vanguard and Invesco accounted for the top ETFs in six of 14 categories listed by our report, smaller product sponsors like ARK, VanEck, Direxion and Guggenheim were also represented.

In most ETF categories, a portfolio concentrated within industry sub-sectors or specific geographies outperformed its more diversified peers. For example the VanEck Vectors Semiconductor ETF outperformed broad technology, style-based and traditional index products to become the best performing large-cap ETF of 2017.

These are the best-performing ETFs of 2017 from each category:

U.S. Multi-cap Stocks
ARK Web x.0 ETF (ARKW)
2017 Return: 87.32%
3-year Annualized Return: 32.14%
AUM: $237 Million

U.S. Large-Cap Stocks
VanEck Vectors Semiconductor ETF (SMH)
2017 Return: 38.44%
3-year Annualized Return: 22.74%
AUM: $1 billion

U.S. Mid-Cap Stocks
iShares Russell Midcap Growth ETF (IWP)
2017 Return: 24.94%
3-year Annualized Return: 9.61%
AUM: $8.5 billlion

U.S. Small-/Micro-Cap Stocks
iShares Russell 2000 Growth ETF (IWO)
2017 Return: 22.25%
3-year Annualized Return: 10.02%
AUM: $9.1 billion

Global & International Stocks
ARK Innovation ETF (ARKK)
2017 Return: 87.34%
3-year Annualized Return: 23.39%
AUM: $380 million

Emerging & Frontier Markets Stocks
Guggenheim China Technology ETF (CQQQ)
2017 Return: 74.32%
3-year Annualized Return: 22.59%
AUM: $388 million

Fixed Income
SPDR Barclays Capital International Corp (IBND)
2017 Return: 14.84%
3-year Return:  0.81%
AUM: $198 million

Commodity
PowerShares DB Base Metals Fund (DBB)
2017 Return: 30.09%
3-year Annualized Return: 7.03%
AUM: $314 million

Currency
CurrencyShares Euro Trust (FXE)
2017 Return: 13.05%
3-year Annualized Return: -1.14%
AUM: $272 million

Real Estate
Vanguard Global Ex-U.S. Real Estate (VNQ)
2017 Return: 29.62%
3-year Annualized Return: 8%
AUM: $5.7 billion

Multi-Asset
Pacer Trendpilot US Large Cap ETF (PTLC)
2017 Return: 21.41%
3-year Annualized Return: N/A
AUM: $731 billion

Hybrid
SPDR Barclays Capital Convertible Bond (CWB)
2017 Return: 15.69%
3-year Annualized Return: 7.9%
AUM: $4 billion

Volatility
iPath S&P 500 VIX Mid-Term Futures ETN
2017 Return: -49.78%
3-year Annualized Return: - 29.52%
AUM: $39 million

Leveraged
Direxion Daily Homebuilders & Supplies (NAIL)
2017 Return: 268.73%
3-year Annualized Return: N/A
AUM: $83 million