It has been about a month since the last earnings report for Valero Energy (VLO). Shares have added about 32% in that time frame, outperforming the S&P 500.Will the recent positive trend continue leading up to its next earnings release, or is Valero Energy due for a pullback? Before we dive into how investors and analysts have reacted as of late, let's take a quick look at the most recent earnings report in order to get a better handle on the important drivers. Valero Q4 Earnings Beat EstimatesValeroreported fourth-quarter 2020 loss of $1.06 per share, narrower than the Zacks Consensus Estimate of a loss of $1.48. In the year-ago quarter, the company reported earnings of $2.13 per share.Total revenues fell from $27,879 million in the prior-year period to $16,604 million. Moreover, the top line missed the Zacks Consensus Estimate of $18,318 million.The narrower-than-expected loss can be attributed to lower cost of sales. The positives were partially offset by lower refinery throughput volumes, ethanol production and renewable diesel sales. Higher refining operating expenses also added to the woes.Segmental PerformanceOperating loss at the Refining segment was reported at $377 million against a profit of $1,419 million in the year-ago quarter. Lower refinery throughput volumes amid the coronavirus pandemic affected the segment.In the Ethanol segment, it reported operating profit of $15 million compared with $36 million in fourth-quarter 2019. The downside was due to lower margins stemming from higher corn prices and reduced prices of ethanol. Moreover, production volumes averaged 4.1 million gallons per day, down 197 thousand gallons from the year-ago quarter.Operating income at the Renewable Diesel segment decreased to $127 million from $541 million in the year-ago period owing to a decline in renewable diesel sales volumes. The segment sales averaged 618 thousand gallons per day for the fourth quarter, down from 844 thousand gallons in the year-ago period.Cost of SalesTotal cost of sales decreased to $16,834 million from the year-ago figure of $25,876 million. Operating expenses, cost of materials, and general & administrative costs decreased year over year.Throughput VolumesFor the quarter, refining throughput volumes were 2,550 thousand barrels per day (Mbpd), significantly down from the prior-year quarter’s 3,018 Mbpd.In terms of feedstock composition, sweet crude, medium/light sour crude and heavy sour crude accounted for 49.3%, 12.4% and 14.4%, respectively, of its total volume. The remaining volumes came from residuals, other feedstock, and blendstocks and others.The Gulf Coast contributed approximately 57.7% to total throughput volume. Mid-Continent, North Atlantic and West Coast regions accounted for 15.8%, 16.4% and 10.1%, respectively, of the total throughput volume.Throughput MarginsRefining margin per barrel of throughput decreased to $4.64 from the year-ago level of $10.90. Refining operating expense per barrel was $4.40 compared with $3.93 in the year-ago quarter. Depreciation and amortization expenses increased to $2.27 a barrel from $1.89 in the prior-year quarter. As such, adjusted refining operating loss was recorded at $2.03 per barrel of throughput against the year-ago profit of $5.08.Capital Investment & Balance SheetFourth-quarter capital investment totaled $622 million. Of the total amount, $214 million was allotted for sustaining the business. Through the December quarter, the leading independent refiner and marketer of petroleum products returned $400 million to stockholders as dividend payments.At quarter-end, Valero had cash and cash equivalents of $3,313 million, lower than the third-quarter level of $4,047 million. As of Dec 31, 2020, it had a total debt of $14,677 million compared with $15,213 million in the third quarter. Its debt to capitalization was 43.8%.GuidanceThe company expects capital investment for this year to be $2 billion. Of the total, 60% will likely be used for business sustaining purposes and the rest will be utilized for growth projects. Notably, around 50% of its growth capital will be allotted for the renewable diesel business’ expansion.Valero expects the Diamond Pipeline expansion and Pembroke Cogen project to come online in the fourth and third quarter of 2021, respectively. The Port Arthur Coker project is scheduled to be completed in 2023. The company intends to quadruple renewable diesel production capacity by 2023. With low-carbon fuel policies being adopted by economies around the globe, demand for renewable fuel is expected to increase in the coming days.How Have Estimates Been Moving Since Then?In the past month, investors have witnessed an upward trend in fresh estimates. The consensus estimate has shifted -6.3% due to these changes.VGM ScoresAt this time, Valero Energy has a poor Growth Score of F, however its Momentum Score is doing a lot better with an A. However, the stock was allocated a grade of C on the value side, putting it in the middle 20% for this investment strategy.Overall, the stock has an aggregate VGM Score of D. If you aren't focused on one strategy, this score is the one you should be interested in.OutlookEstimates have been trending upward for the stock, and the magnitude of this revision indicates a downward shift. It comes with little surprise Valero Energy has a Zacks Rank #2 (Buy). We expect an above average return from the stock in the next few months.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 Valero Energy Corporation (VLO): Get Free Report To read this article on Zacks.com click here.