Last year was an excellent one for U.S. equities with the SPDR S&P 500 (NYSEArca: SPY) posting a gain of 32.3% when accounting for dividends paid.

However, big energy was something of a big laggard last year. Twenty-one of the 30 members of the Dow Jones Industrial Average posted 2013 gains of at least 20%, but Exxon Mobil (NYSE: XOM) and Chevron (NYSE: CVX), the two largest U.S. oil companies, were not on that list. Underwhelming performances by those oil giants weighed on some popular energy ETFs.

For example, the Energy Select Sector SPDR (NYSEArca: XLE) was merely the sixth-best of the nine sector SPDRs last year, beating only its materials, staples and utilities counterparts. Exxon and Chevron combine for nearly 31% of XLE’s weight. The good news is energy stocks are cheap.

“Energy stocks also have the lowest price/earnings, price/sales, and price/cash flow ratios of any equity sector. Along with its attractive relative valuation, the sector is also in solid financial condition. In fact, the energy sector’s debt as a percentage of total capital is the lowest of any sector,” according to Morningstar analyst John Gabriel.

Still, XLE and rivals such as the Vanguard Energy ETF (NYSEArca: VDE) lagged the S&P 500 last year even as U.S. oil production soared. The U.S. shale boom has the world’s largest economy rivaling the likes of Russia and Saudi Arabia for global oil production dominance and it will be just a matter of time before the U.S. is passed by China for title of world’s largest oil importer. [Oil ETF Looks to Breakout]

Integrated oil stocks, almost a third of XLE’s weight, were left behind last year and although oil services companies appear to be finding a groove of sorts, that sub-industry represents just 17% of XLE’s weight. [Oil Services ETFs in a Cyclical Groove]