The energy has been one of the top-performing sectors of this year driven by an improving demand outlook as the economy recovers. Better-than-expected earnings from the two big oil giants — Exxon Mobil XOM and Chevron CVX — are expected to continue fueling the strong trend.Exxon Mobil posted its biggest quarterly profit in more than a year on rebounding demand for oil, gas and chemicals while Chevron logged profits for the second consecutive quarter on rising demand for petroleum products and an increase in oil prices (see: all the Energy ETFs here).Earnings in FocusThe largest U.S. oil producer Exxon Mobil came up with earnings of $1.10 per share, beating the Zacks Consensus Estimate of $1.02. The company had incurred a loss of 26 cents in the year-ago quarter. Revenues more than doubled from the year-ago quarter to $67.74 billion and edged past the estimate of $63.73 billion.Chevron reported earnings of $1.71 per share, outpacing the Zacks Consensus Estimate of $1.54. The company had incurred a loss of $1.59 per share in the year-ago period. Revenues jumped 179% year over year to $37.6 billion and edged past the consensus mark of $35.6 billion. With free cash flow reaching the highest in two years, the company plans to resume stock repurchases in the third quarter at an annual rate of $2 billion to $3 billion a year.ETFs in FocusFollowing the results, energy ETFs with the largest allocation to the energy behemoths are in focus. Below we highlight the most popular ones in details.Energy Select Sector SPDR XLEThis is the largest and the most-popular ETF in the energy space with AUM of $23 billion and an average daily volume of 27.5 million shares per day. Expense ratio is 0.12%. The fund follows the Energy Select Sector Index and holds 22 securities in its basket. Exxon Mobil and Chevron occupy the top two spots with 23.7% and 21.3% share, respectively. The product has a Zacks ETF Rank #2 (Buy) with a High risk outlook (read: Play Revenue Growth With 5 ETFs As Earnings Hopes Too Upbeat).iShares U.S. Energy ETF IYEThis ETF tracks the Dow Jones U.S. Oil & Gas Index, giving investors exposure to U.S. companies that produce and distribute oil and gas. It holds 35 stocks in its basket with AUM of $2.2 billion and an average daily volume of about 2.3 million shares. The product charges 42 bps in fees per year from its investors. Exxon Mobil and Chevron occupy the top two positions in the basket, taking the bigger chunk of assets at 23.4% and 18.9%, respectively. The product has a Zacks ETF Rank #3 (Hold) with a High risk outlook.Vanguard Energy ETF VDEThis fund manages $5 billion in asset base and provides exposure to a basket of 94 energy stocks by tracking the MSCI US Investable Market Energy 25/50 Index. The product sees a good volume of about 1 million shares and charges 10 bps in annual fees. Here again, Exxon and Chevron are the two leading firms with respectively 21.8% and 16.4% allocation. VDE has a Zacks ETF Rank #2 with a High risk outlook (read: Here's Why You Should Bet on Energy ETFs Now).Fidelity MSCI Energy Index ETF FENYThe fund follows the MSCI USA IMI Energy Index, holding 99 stocks in its basket. Of these, XOM and CVX take the top two spots at 21.9% and 16.5%, respectively. The product charges 8 bps in annual fees and trades in a good volume of around 931,000 shares. It has accumulated $901.5 million in its asset base and has a Zacks ETF Rank #3 with a High risk outlook. 5 Stocks Set to Double Each was hand-picked by a Zacks expert as the #1 favorite stock to gain +100% or more in 2021. Each comes from a different sector and has unique qualities and catalysts that could fuel exceptional growth. Most of the stocks in this report are flying under Wall Street radar, which provides a great opportunity to get in on the ground floor. Today, See These 5 Potential Home Runs >>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Chevron Corporation (CVX): Free Stock Analysis Report Exxon Mobil Corporation (XOM): Free Stock Analysis Report Energy Select Sector SPDR ETF (XLE): ETF Research Reports iShares U.S. Energy ETF (IYE): ETF Research Reports Vanguard Energy ETF (VDE): ETF Research Reports Fidelity MSCI Energy Index ETF (FENY): ETF Research Reports To read this article on Zacks.com click here. Zacks Investment Research