This year's Fortune 500 list featured seven U.S.-based public construction/engineering firms. The ranking revealed that five out of the seven companies rose in the rankings, but one firm dropped off the list entirely. KBR, which ranked at number 424 last year, slipped off the 500 threshold in 2015 and claimed the 501st spot. Fortune 500 ranks U.S. companies with publicly available earnings information based on their gross revenue after adjustments. 

The general upward trend reinforced the Engineering News-Record's Top 400 contractors list, which found that total 2015 revenue of the Top 400 contractors reached $344.14 billion — a 3.7% increase from 2014 and a record high for the annual list. The ENR noted, however, that revenues earned abroad plummeted 21.1% to $49.79 billion, with the global decline in mining and energy projects leading that slide. The ENR list also includes privately held companies.

In a positive prediction for the industry, CMD Group forecast last month that the dollar amount of year-over-year residential and nonresidential construction starts will increase by 7.4% in 2016. CMD expects the primary drivers of construction starts to be the nonresidential building categories of office buildings, transportation terminals and medical facilities, as well as the civil engineering category of roads and bridges.

Looking forward in the engineering/construction industry, Congress' passage of a long-term highway bill in December 2015 could lead to a boon in highway construction. Building for oil and gas companies took a major hit in the past year due to falling oil prices, but the recent rebound in oil prices signals positive news for contractors in that market.

Why did the majority of firms experience a more successful 2015? We delve into each company's numbers and business activity in 2015. 

Fluor: #155

• Revenue: $18.114 billion (down 15.9%)
• Profits: $413 million (down 19.3%)
• Number of employees: 38,758
• Rank last year: 136 (drop of 19 spots)
• Years on Fortune 500 list: 15

Global construction and engineering giant Fluor is based in Irving, TX. In the company's earnings report at the end of 2015, Fluor said the decline in revenue stemmed from its disappointing power segment. The company ranked second on the ENR Top 400 contractors list last month. A consortium led by Fluor recently won the P3 contract for the $5.6 billion Maryland Purple Line project. The firm was also named one of the "World’s Most Admired Companies" by Fortune in February.

AECOM: #156

• Revenue: $17.990 billion (up 115.3%)
• Profits: -$155 million (down 167.4%)
• Number of employees: 92,000
• Rank last year: 343 (up 187 spots)
• Years on Fortune 500 list: 8

Based in Los Angeles, AECOM provides construction, architecture, design and engineering services. In its earnings report at the end of 2015, the company said the surge in revenue was due largely to mergers last year, as well as its design and consulting services division in the Americas and its management services segment. AECOM ranked sixth on the ENR's Top 400 contractors list this year, up from the eighth spot in the previous year. A recent report found that Tishman Construction — which is owned by AECOM — dominates construction in New York City, snagging three times the square footage of its closest competitor. AECOM was also selected earlier this year to build SpaceX's Hyperloop test track. 

Jacobs Engineering Group: #235

• Revenue: $12.115 billion (down 4.6%)
• Profits: $303 million (down 7.7%)
• Number of employees: 56,950
• Rank last year: 239 (up 4 spots)
• Years on Fortune 500 list: 16

Pasadena, CA,-based Jacobs offers design, construction, maintenance and consulting services for clients in oil and gas, infrastructure and other industries. In July 2015, the company named Steven Demetriou as its new president and CEO. Jacobs ranked 13th on the ENR's Top 400 contractors list this year, down from the 10th spot in 2015. In its 2015 earnings report, Demetriou said the company's recent reorganization efforts to focus on four main lines of business should help cut costs and boost profits going forward. The four global lines of business include industrial; buildings and infrastructure; petroleum and chemicals; and aerospace and technology.

Peter Kiewit Sons': #314

• Revenue: $8.992 billion (down 13.4%)
• Profits: $251 million (down 28.3%)
• Number of employees: 22,000
• Rank last year: 286 (drop of 28 spots)
• Years on Fortune 500 list: 17

Kiewit, based in Omaha, NE, operates in several sectors, including transportation, oil and gas, offices and mining. The firm is owned by Kiewit family members and employees. Kiewit ranked fifth on the ENR's Top 400 contractors list again this year. Recently, a division of Kiewit — Kiewit Infrastructure — began the first stages of Project Neon, the Nevada Department of Transportation’s $1.5 billion plan to renovate the Las Vegas Interstate 15 and U.S. Highway 95 interchange.

Quanta Services: #352

• Revenue: $7.632 billion (down 2.8%)
• Profits: $311 million (up 4.8%)
• Number of employees: 24,500
• Rank last year: 361 (up 9 spots)
• Years on Fortune 500 list: 4

Houston-based Quanta provides construction and engineering services for the oil and gas and electric power industries. During a conference call about Quanta's 2015 earnings, company executives blamed factors "outside of our control" for the drop in revenue, including falling oil prices and severe weather. The contractor also admitted fault in suffering losses on its combined cycle gas power plant project in Alaska. However, Quanta said its strong mainline pipe backlog should bring higher profits in 2016.

EMCOR Group: #381

• Revenue: $6.723 billion (up 4.3%)
• Profits: $172 million (up 2.1%)
• Number of employees: 29,000
• Rank last year: 421 (up 40 spots)
• Years on Fortune 500 list: 16

Based in Norwalk, CT, EMCOR provides electrical and mechanical construction services in the commercial, utility, industrial, and institutional sectors. In its 2015 earnings report, the company announced it had reached record revenues in 2015. Backlog at the end of 2015 was at EMCOR's highest level since 2008. The company said that backlog growth was due largely to its U.S. mechanical construction and building services divisions, while its U.S. industrial services and electrical construction segments saw backlogs decline in 2015. EMCOR added that weak levels of "anticipated capital spending" in the oil and gas industries continues to be an ongoing problem.

CH2M Hill: #478

• Revenue: $5.362 billion (down 1.0%)
• Profits: $80 million (unchanged)
• Number of employees: 22,000
• Rank last year: 480 (up 2 spots)
• Years on Fortune 500 list: 8

Englewood, CO,-based CH2M is a global engineering firm that offers construction, consulting, and design services. The employee-owned company operates an internal stock market and is currently working on the massive Panama Canal expansion project. Last year, the firm announced its plans to rebrand as simply CH2M to create a "refreshed" company focus. CEO Jacqueline Hinman said in CH2M's 2015 annual report that last year served as a rebound year for the company after 2014 marked the worst year in its 70-year history. She considered 2015 a success, as CH2M was able to cut costs and see a rise in stock prices.