Every four years, the American Society of Civil Engineers issues a report card on the condition of the nation's infrastructure. In 2013, the country received a sad D+ – something that then-candidate Donald Trump highlighted during his presidential campaign. The recently released 2017 report card is no better – another D+. Clearly the need for an overhaul is there. But what exactly that means, who pays for it and how much should be spent is up for question.

On Monday, President Trump unveiled his administration's proposal: a new $1.5 trillion infrastructure plan that includes a $200 billion contribution from Washington over the next decade meant to spur another $1.3 trillion in spending by cities, states and the private sector. While it is unclear whether the specific plan will get through Congress – Democrats largely see the plan as falling short and Republicans are largely unwilling to push through another big spending measure – it is apparent that the administration is prioritizing rebuilding infrastructure, as has been expected. (See: Infrastructure Spending: Watch the U.S. Fall behind).

A new focus on infrastructure is encouraging to investors who seek exposure to this niche. (See: How Big Investors Will Profit From Trump's Infrastructure Bonanza.) On Monday, the stocks of major infrastructure companies saw little movement following the news of Trump's proposal, but longer term, those stocks stand to benefit.

It is important to note that infrastructure is an extremely broad category, encompassing transportation, communications, water and electricity – representing hundreds, if not thousands, of equities. Selection is essential to success, since not all "infrastructure" stocks will take off under the proposed spending. (See: Build Your Portfolio With Infrastructure Investments.)

That being said, well-diversified companies positioned to handle major infrastructure projects should do well over the medium- to long-term. Here's a look at four of the most promising infrastructure stocks. All figures are accurate as of February 12, 2018.

1. AECOM (ACM)

AECOM's business is designing, financing, building and operating infrastructure assets for federal and state governments and businesses. With a market cap of $5.56 billion and fiscal 2017 annual revenue of $18.20 billion, the company is well positioned to handle a large influx of new government projects. AECOM's recently reported fiscal first-quarter 2018 results rose from a year earlier and surpassed estimates.

AECOM recently merged with rival URS to enhance its focus on the energy and transportation sectors, areas that are sure to see new spending under the Trump administration if the president can pass his infrastructure package. In fact, AECOM stock surged sharply on Trump's victory, rising from $27.61 on Nov. 8, 2016, to $37.54 a week later, reaching a high of over $40 in December 2016. As of February 12, 2018, the stock was trading at $34.94, down 6% year-to-date. The stock has a median 12-month price target of $41.27, suggesting 18% upside potential, and it earns a consensus rating of "Buy." (See also: AECOM to Buy Shimmick, Make Most of Infrastructure Spend.)

2. Vulcan Materials Company (VMC)

"Construction aggregate" sounds like a boring business, but these little bits of gravel, limestone and sand form the foundation of all sorts of building projects, including high-priority infrastructure items such as bridges, roads and industrial plants. Vulcan is the largest producer of these construction products, and it estimates that 75% of the population growth in the coming years will take place in states currently served by the company.

Vulcan has a market cap of $16.82 billion and generated annual revenue of $3.59 billion in 2016, which equates to a revenue growth rate of nearly 9% year over year. As of February 12, the stock was trading at $127.16, a year-to-date decline of less than 1%. Analysts have been lowering earnings forecasts over the last few months, suggesting that there may be concerns about the company's growth prospects. Nonetheless, the 12-month stock price target suggests strong growth over the next year. Its median price target is $144.92 (implying 14% upside potential), and the consensus rating is Outperform. (See also: Vulcan Materials' Inorganic Growth in Full Swing.)

3. Martin Marietta Materials, Inc. (MLM)

Martin Marietta is a leading manufacturer of cement, asphalt and other building materials, with a strong presence in states such as North Carolina, Texas, Colorado and Georgia that have booming construction economies. The company recently kicked off a massive project in Texas known as the Medina Rock & Rail, strengthening its foothold in the lucrative Texas market. Last year proved to be a record year in terms of the company's revenue, which hit nearly $3.9 billion.

Martin Marietta is based in Raleigh, North Carolina, and it has a market cap of $13.37 billion. Net income was up last year by 47% to $421 million, and earnings per share rose 31% to $6.63. The stock currently trades at $212.76, down 3.75% year-to-date. The average 12-month price target of $246.93 suggests upside potential of nearly 9%. (See also: Martin Marietta to Buy Bluegrass, Boost Aggregates Business.)

4. Quanta Services, Inc. (PWR)

Quanta is a specialty contractor providing infrastructure services primarily to the oil and gas and electrical power industries, all of which stand to benefit under Trump's infrastructure spending plans. Quanta is also a prime provider of oil and gas pipelines and renewable energy infrastructure, including onshore and inland hydroelectric projects.

Quanta has a market cap of $5.5 billion and posted annual revenue of $7.65 billion in 2016, on par with the previous year's revenue of $7.57 billion. As of February 12, the stock was trading at $33.98, down 13% year-to-date. Its 12-month price target of $45.32 leaves room for over 33% growth. (See also: Quanta Services Q1 Earnings Miss, Revenue Up Y/Y.)

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