7 Best Small-Cap Data Center Infrastructure Stocks — June 2026

Hyperscale data-center capex is running at $300-400B/year globally and accelerating. Microsoft, Meta, Google, Amazon, and Oracle collectively committed to >40 GW of new generation capacity by 2030; the build-out behind that demand requires concrete, copper, fiber, chilled water, switchgear, and the mechanical contractors who put it all together. The big-cap winners — Vertiv, Eaton, nVent, Schneider — are obvious and well-owned. The small-cap layer (market cap <$2B) covers the specialty contractors, fiber and cable suppliers, structured piping, and precision-timing components that ship inside everyone else's deliverable.

Below: seven US-listed small-cap names with current operating exposure to data-center build-out — ranked by our May 24 score snapshot. This list is deliberately distinct from our June 2026 Power & Grid list, which covers the generation and transmission layer. This list covers inside-the-fence — what happens once the power feeder reaches the substation gate.

What Counts As Data Center Infrastructure

Hyperscale data center build-out splits into roughly four physical layers: (a) the site-prep and structural work — concrete, steel, civil; (b) the mechanical systems — chilled-water loops, CRAH units, immersion cooling, controls; (c) the electrical distribution — UPS, PDUs, switchgear, busways; and (d) the connectivity layer — fiber backbone, copper structured cabling, network gear.

The mega-caps own most of the dollar value at the equipment level. The small-cap exposure sits in the specialty layers between them: piping for the mechanical loops, hardware that physically attaches transmission lines to the substation, precision oscillators inside the network gear, structured cabling, and the mechanical contractors who actually install the systems. None of these names are pure data-center plays — diversified industrial customers are still the larger end-market for most of them. That diversification is the structural argument: small-cap DCI exposure with the optionality on data-center capex without single-customer concentration risk.

The Names

PPIH — Perma-Pipe International Holdin

Score: 72.4 (SOLID) | Market cap: $0.26B | Revenue YoY: +33.2% | Rule of 40: 47.1 | Cash runway: net cash

Perma-Pipe makes pre-insulated piping systems — the high-efficiency thermal piping used in district cooling, district heating, and increasingly in hyperscale data-center chilled-water loops. As AI-driven rack densities push 50-100 kW per cabinet, air cooling alone no longer works; liquid-cooled designs route chilled water through district-style loops that look a lot more like a campus utility than a building HVAC system. PPIH ships the piping. Revenue +33% YoY, Rule of 40 ~47, net cash. The structural quality of the financials is what drives the SOLID grade despite the small market cap. → See full PPIH score card

PLPC — Preformed Line Products Company

Score: 69.1 (SOLID) | Market cap: $1.51B | Revenue YoY: +12.7% | Rule of 40: 21.0 | Cash runway: net cash

Preformed Line Products makes hardware for high-voltage transmission and distribution lines — splices, dead-ends, vibration dampers, fiber-optic cable suspension. Every data-center site needs new feeder lines from substation to gate, and PLPC's products sit in the supply chain between the transmission utility and the data-center construction firm. Revenue +13% YoY, Rule of 40 ~21, net cash, durable industrial-quality balance sheet. Indirect data-center exposure but high-quality operating business. → See full PLPC score card

RFIL — RF Industries, Ltd.

Score: 66.9 (SOLID) | Market cap: $0.15B | Revenue YoY: +24.3% | Rule of 40: 26.5 | Cash runway: net cash

RF Industries makes RF and fiber-optic connectors, cable assemblies, and integrated cabinet systems for telecom, industrial, and data-center networking. The 2025 reorganization around the Microlab/FMI acquisitions consolidated cabling, RF passives, and integrated rack-level assemblies under one roof. Revenue +24% YoY, Rule of 40 ~26, net cash. Tiny market cap ($150M) limits institutional ownership but is also the structural reason there is asymmetric upside if the data-center-cabling pipeline keeps expanding. → See full RFIL score card

LMB — Limbach Holdings, Inc.

Score: 66.9 (SOLID) | Market cap: $1.21B | Revenue YoY: +24.7% | Rule of 40: 32.6 | Cash runway: net cash

Limbach is a mechanical-systems contractor — HVAC, plumbing, controls — focused on mission-critical buildings. The owner-direct segment has grown into data centers, healthcare facilities, and life-sciences buildings, where engineering complexity and uptime requirements command higher gross margins than standard commercial construction. Revenue +25% YoY, Rule of 40 ~33, net cash. This is the closest thing in the US small-cap universe to a pure-play operating exposure to data-center mechanical build-out. → See full LMB score card

LYTS — LSI Industries Inc.

Score: 63.0 (SOLID) | Market cap: $0.86B | Revenue YoY: +22.1% | Rule of 40: 28.3 | Cash runway: net cash

LSI Industries makes commercial LED lighting, digital displays, and graphics systems — primarily for retail, fuel-and-convenience, and increasingly for industrial sites including warehouses and data-center facility lighting. Not a data-center pure-play, but the LED + control-system mix benefits from the broader commercial-construction capex cycle that the hyperscale build-out drags along with it. Revenue +22% YoY, Rule of 40 ~28, net cash. Diversified industrial; low concentration risk on any single end-market. → See full LYTS score card

OCC — Optical Cable Corporation

Score: 61.8 (SOLID) | Market cap: $0.10B | Revenue YoY: +9.5% | Rule of 40: 8.9 | Cash runway: net cash

Optical Cable Corporation is the picks-and-shovels fiber-optic structured-cabling play — tight-buffered fiber, hardened outdoor cabling, and copper structured cabling for data centers, military bases, and industrial facilities. Tiny market cap (~$97M) means liquidity-constrained for institutional buyers, but the structural-cabling certifications and long-tenured contractor relationships are the moat. Revenue +9.5% YoY, net cash. Honest framing: this also appears on our June 2026 AI Photonics list — the company sits at the intersection of both themes. → See full OCC score card

MPTI — M-tron Industries, Inc.

Score: 61.6 (SOLID) | Market cap: $0.26B | Revenue YoY: +11.0% | Rule of 40: 29.9 | Cash runway: net cash

M-tron Industries makes precision frequency-control devices — crystal oscillators, filters, frequency synthesizers — for aerospace, defense, satellite, and high-reliability data-center equipment. As data-center networking pushes 800G and 1.6T optical, the precision-timing requirements on the switch and the line-card side rise meaningfully. Revenue +11% YoY, Rule of 40 ~30, net cash. Defense-and-aerospace mix gives durable backlog; the data-center-equipment exposure is the growth optionality on top. → See full MPTI score card

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How to Think About This Basket

The seven names split into three exposure groups. Mechanical and contracting (LMB, PPIH) is the most direct operating exposure to the data-center build cycle — LMB installs the mechanical systems, PPIH ships the chilled-water piping. Electrical and cabling (PLPC, RFIL, OCC, MPTI) feeds the equipment supply chain — transmission hardware, RF and fiber connectors, structured cabling, precision oscillators. Commercial-construction adjacency (LYTS) captures the broader capex cycle that hyperscale build-out drags along.

A practical mix: 45% mechanical/contracting for direct operating leverage, 45% electrical/cabling for diversified exposure across the equipment supply chain, 10% construction adjacency. The bear case across the basket: data-center build cycles can stall if the transformer + interconnect-queue bottleneck doesn't loosen by 2027. These names re-rate back to standard industrial multiples if the AI capex narrative compresses.

How We Scored

Our model rates every US small-cap stock (market cap <$2B) across eight fundamentals: revenue growth, gross margin, cash runway, debt/equity, P/S ratio, Rule of 40, insider ownership, and 12-month dilution. Sector-adjusted where appropriate. Scores refresh weekly. See methodology or browse all small-cap industrial stocks.

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Data as of May 28, 2026. Updated monthly. Past performance does not guarantee future results. Not investment advice.