Quanta vs. MasTec: Which AI Infrastructure Stock is the Better Buy?

Sraddha Singha May 22, 2026

PWR MTZ

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Key Takeaways

Quanta's backlog reached a record $48.5B as of Q1 2026 as AI-driven power demand accelerated.
MasTec raised its 2026 guidance after backlog climbed 28% year over year to $20.3B as of Q1 2026.
PWR targets transformer and fabrication expansion while MTZ boosts data center work.

The United States infrastructure contracting companies are benefiting from surging investment in power grids, renewable energy, telecom and AI data center buildouts. Market players like Quanta Services, Inc. (PWR - Free Report) and MasTec, Inc. (MTZ - Free Report) , that compete in utility and energy infrastructure markets, are banking on these long-term tailwinds.

Quanta is a leading provider of electric power and utility infrastructure solutions, with a strong focus on transmission, distribution and large-scale energy projects. Meanwhile, MasTec engages in the engineering, building, installation, maintenance and upgrade of energy, communication, utility and other infrastructure.

Let’s closely compare the fundamentals of the two infrastructure stocks to determine which one is a better investment now.

The Case for Quanta Stock

Quanta’s mix across transmission and distribution, grid hardening, renewable integration and generation gives it multiple paths to participate as those plans become multi-year capital programs. Surging AI-related power demand and expanding utility investments are driving data center project opportunities, making data centers a central pillar of the company’s long-term growth strategy. PWR achieved a record total backlog of $48.5 billion as of March 31, 2026, providing a clear and durable runway for long-term growth. This record includes a 12-month backlog of $28.2 billion and remaining performance obligations of $26.2 billion. The Electric Power Infrastructure Services segment accounted for $40.1 billion of the total backlog.

Besides, Quanta’s ability to self-perform 80-85% of its work keeps more of the execution under its control and can reduce reliance on subcontractors on large programs. It is heavily investing in deepening its vertical supply chain to offset the ongoing global uncertainties and rising inflation. The company expects to invest $500-$700 million over the next several years in power transformer manufacturing facilities and related strategy, which is intended to double transformer manufacturing capacity. Besides, it is also planning to nearly double off-site manufacturing, fabrication and logistics facilities to about 6.7 million square feet.

At its March 2026 Investor Day, management outlined an opportunity to more than double adjusted EPS by 2030, with a 15-20% adjusted EPS growth target and a total addressable market estimate of $2.4 trillion through 2030, anchoring a longer-cycle demand backdrop for Quanta’s platform.

Moreover, the company aims to sustain its integration discipline while continuing to layer in capabilities that fit its self-perform model. In the first quarter of 2026, acquired businesses contributed about $460 million of Electric revenues and about $335 million of Underground and Infrastructure revenues, supporting growth beyond organic end-market demand. Management continues to describe an active pipeline of strategic opportunities and a target leverage profile of 1.5-2x, which frames future tuck-in activity alongside organic investment.

The Case for MasTec Stock

MasTec is also gaining from sustained demand across multiple infrastructure end markets. Communications growth is supported by rising data consumption, fiber deployment and multiyear broadband initiatives, including BEAD funding. Power Delivery demand is driven by grid modernization, system hardening and rising electricity needs, with data centers expected to materially increase power consumption. Clean Energy and Infrastructure is seeing growth across renewables, industrial projects and mission-critical facilities, including data centers. This diversification reduces reliance on any single market and supports more stable long-term growth.

Backlog reached a record $20.3 billion in the first quarter of 2026, increasing approximately 7% sequentially and 28% year over year, supported by a 1.4x book-to-bill ratio. Management highlighted that backlog does not fully capture ongoing negotiations and verbal awards, indicating additional upside potential. Management highlighted growing opportunities in fiber interconnectivity, transmission infrastructure and turnkey data center construction, positioning MasTec at the center of several multiyear infrastructure trends.

Owing to the robust market trends, MTZ raised its 2026 guidance, as it now expects revenues of approximately $17.5 billion (from $17 billion), adjusted EBITDA of $1.5 billion (from $1.45 billion) and EPS of $8.79 (from $8.40 per share), representing solid year-over-year growth across all metrics. This outlook reflects sustained demand, backlog conversion and improving operational execution, supporting continued earnings growth momentum.

In the first quarter of 2026, adjusted EBITDA increased 73% year over year, with margin expansion of 170 basis points. Power Delivery and Pipeline segments showed notable margin improvements, supported by better execution and project performance. MTZ expects continued margin expansion across segments in 2026, with full-year EBITDA guidance raised to approximately $1.5 billion and margins improving modestly. This reflects a better project mix, pricing improvements and operational discipline.

However, variability in project timing, dwindling cash flow, increasing inflation risks and global political unrest are proving to be near-term growth restrictions for the company. MasTec operates in markets influenced by government policy and regulatory approvals. Renewable energy investment remains tied to policy frameworks and potential changes to incentive structures could impact project activity in Clean Energy and Infrastructure. These factors introduce uncertainty into project pipelines despite favorable long-term demand trends.

Stock Performance & Valuation

As witnessed from the chart below, in the year-to-date period, Quanta’s share price performance is below MasTec's but significantly above the broader Construction sector.