Willdan vs. Tetra Tech: Which Infrastructure Stock Has More Upside?

The infrastructure consulting space is being reshaped by electrification, AI-driven data center expansion, water scarcity and defense modernization. Two companies well-positioned within this evolving landscape are Willdan Group, Inc. WLDN and Tetra Tech, Inc. TTEK. While both operate at the intersection of public-sector infrastructure and private capital investment, their strategic focus and growth engines differ meaningfully.

Willdan is increasingly leveraged to U.S. electricity load growth, grid modernization and municipal advisory services. Tetra Tech, on the other hand, is a global leader in water, environmental and defense consulting, with expanding margins and a diversified international base. With infrastructure spending accelerating across utilities, municipalities and defense agencies, the comparison between these two stocks is particularly relevant now.

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

Market Performance Snapshot: WLDN Vs TTEK

WLDN’s 238% rally over the past year underscores strong investor enthusiasm for electrification and grid modernization exposure. TTEK’s 11% gain reflects steadier performance aligned with its defensive, water-focused and globally diversified business model.

WLDN Vs TTEK Price Performance

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Valuation and Earnings Revision Contrast: WLDN Vs TTEK

Willdan trades at a premium multiple of 24.68X forward earnings versus Tetra Tech’s 20.65X. Yet earnings revision trends favor Tetra Tech, where upward estimate adjustments provide incremental support for valuation stability. Willdan’s unchanged earnings per share (EPS) estimate suggests expectations may already be well embedded in the share price.

WLDN Vs TTEK Valuation - P/S Ratio (Forward 12-Month)

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The Case for Willdan Stock

Willdan has emerged as one of the strongest performers in the small-cap infrastructure consulting space. In the third quarter of 2025, contract revenue rose 15% year over year to $182 million, while net revenue increased 26% year over year to $95 million, supported by 20% organic growth. Adjusted EBITDA climbed 52.5% year over year to $23.1 million and adjusted EPS jumped 65.8% year over year to $1.21. Management credited growing electricity demand driven by data centers and electrification as key tailwinds. 

Strategically, about 85% of Willdan’s revenue is derived from its Energy segment, which includes policy advisory, energy engineering and program management. The company has built a vertically integrated model serving hyperscalers and utilities — from upfront forecasting and site selection to substation design and energy optimization. Recent wins include a $97 million Alameda County infrastructure upgrade project and multiple substation awards tied to energy storage and grid expansion.

Importantly, Willdan is also broadening its financial advisory footprint. In November 2025, the company announced the acquisition of Compass Municipal Advisors, a registered municipal advisory firm specializing in capital planning, debt issuance management and investment services. The deal expands Willdan’s geographic reach in the Southeastern United States and strengthens its municipal financial consulting capabilities. This enhances Willdan’s ability to support local governments not only with engineering and grid solutions but also with financing strategies for aging infrastructure and growth-related projects.

Management has raised its 2025 financial targets to net revenue of $360–$365 million and adjusted EPS of $4.10–$4.20, reflecting confidence in continued momentum.

That said, valuation and expectations are elevated. The stock trades at 24.68X forward earnings, above Tetra Tech’s 20.65X. Over the past 60 days, the Zacks Consensus Estimate for 2026 EPS has remained unchanged at $4.53, implying 9.6% growth, while revenue is projected to rise 4.8%. The absence of upward revisions may limit near-term multiple expansion. Moreover, after surging 238% over the past year, much of the electrification-driven optimism appears priced in.

WLDN's Earnings Estimate

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The Case for Tetra Tech Stock

Tetra Tech presents a larger, globally diversified infrastructure consulting platform with a strong focus on water, environmental remediation and defense modernization. In the first quarter of fiscal 2026, net revenue totaled $1.04 billion and adjusted EBITDA margin expanded 140 basis points year over year. Adjusted EPS rose 17% year over year to 35 cents. The company raised its fiscal 2026 guidance, now expecting net revenue of $4.15–$4.30 billion and adjusted EPS of $1.46–$1.56.

Segment performance was balanced, with Government Services net revenue up 5% and Commercial & International Group revenue up 10%, accompanied by margin expansion in both segments. International operations — accounting for 48% of net revenue — grew 13% year over year, highlighting diversification beyond U.S. federal spending. Backlog stood at $3.95 billion at quarter-end, offering strong visibility despite a temporary U.S. government shutdown.

Tetra Tech’s strategic emphasis on front-end advisory and high-margin consulting is particularly noteworthy. Management highlighted improving backlog quality and embedded margins. Recent contract wins include large-scale water, environmental and defense programs, such as awards from the U.S. Army Corps of Engineers and Australia Defense. Strategic acquisitions like Halvik are expanding data analytics and infrastructure optimization capabilities, strengthening Tetra Tech’s position in defense and digital modernization markets.

However, near-term estimates indicate fiscal 2026 EPS may decline 3.9% year over year and revenue could fall 8.5%, partly reflecting normalization effects. While the stock has risen just 11% in the past year — significantly lagging Willdan — it trades at a more moderate valuation and benefits from positive estimate revisions, with fiscal 2026 EPS estimates increasing from $1.48 to $1.50 over the past 60 days.

TTEK's Earnings Estimate

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Which Stock Offers Better Upside?

Both companies are positioned to benefit from multi-year infrastructure spending cycles. Willdan offers higher organic growth exposure to electricity load expansion, data center-driven grid investment and now expanded municipal advisory capabilities through Compass. However, its substantial stock appreciation and premium valuation reduce margin for error.

Tetra Tech, by contrast, combines margin expansion, raised fiscal 2026 guidance, strong backlog visibility and improving earnings revisions with a more attractive valuation profile. Its diversified global water and defense exposure provides durable, less cyclical growth drivers.

Considering valuation, estimate trends and risk-reward balance, Tetra Tech currently appears to offer better upside potential. With a Zacks Rank #2 (Buy) compared to Willdan’s Zacks Rank #3 (Hold), Tetra Tech presents a more compelling combination of growth visibility, margin expansion and valuation support at this stage of the infrastructure cycle.