$151.1M Chicago Byte Exchange Phase 3 Tracks 6 LV Systems

Chicago's $151.1 million Phase 3 permit for the Chicago Byte Exchange converts the former Cboe headquarters at 400 S LaSalle Street into a 33-megawatt urban data center. Signal tracks six low-voltage planning lanes on the permit-backed project, producing a conservative $10.4 million Phase 3 LV planning floor and a $16.5 million full-facility capacity cross-check.

Project Overview

The City of Chicago permit record is unusually specific. Permit 101084518 was applied for June 17, issued September 16, 2026, and remains active. Its $151,112,046 reported cost covers Phase 3 of a three-phase interior conversion: new data-center equipment and associated mechanical, electrical, and plumbing upgrades inside an existing Type IA building classified as Business occupancy.

The permit describes a seven-story office building. Legacy's facility material describes approximately 300,500 square feet, more than 100,000 square feet of data-hall white space, and 33 megawatts of committed utility capacity. Those building and floor descriptions do not align perfectly across public sources, so bidders should use the issued drawings—not marketing shorthand—to size risers, floor penetrations, pathways, and material-handling plans.

Phase 1, under permit 101083036, covered demolition across the basement, first through seventh floors, and mechanical penthouse. Phase 2, under permit 101081181, covered $51.1 million of structural reinforcement and electrical distribution from the ComEd vault to upper floors. LVN does not add those values to Phase 3 because the relationship between the phase budgets and the broader redevelopment estimate is not fully documented.

Project	Chicago Byte Exchange / 400 S LaSalle data center conversion
Location	400 S LaSalle Street, Chicago, Illinois 60605
Phase 3 Permit	101084518, issued September 16, 2026
Phase 3 Value	$151,112,046
Facility Capacity	33 MW committed; expansion to 50 MW is described as future utility-dependent capacity
Facility Area	Approximately 300,500 square feet, including 100,000+ square feet of white space
Signal Score	10/10
Tracked LV Systems	6 planning lanes

What Is Actually Under Contract

This is not a speculative site announcement. The city record identifies an issued Phase 3 construction permit, owner entity, architect, general contractor, and three electrical contractors. That also means contractors should not mistake the spotlight for an untouched greenfield buyout. The practical opening is downstream: documented specialty partners, overflow capacity, commissioning support, fiber and security integration, and relationships that can travel with a repeat mission-critical team.

The permit names ARCO/Murray National Construction Company as general contractor. It lists ABCO Electrical Construction, Bonus Electric, and Kelso-Burnett as electrical contractors. No public record reviewed for this spotlight names the structured-cabling, fiber, physical-security, DAS, or AV specialty award, and the six Signal systems should be read as planning and qualification lanes—not as awarded contracts.

Key Players

Role	Company	Source-Backed Position
Owner / Developer / Operator	Legacy Investing	The permit owner is Legacy GI TC 400 Lasalle LLC. Legacy markets the facility as Chicago Byte Exchange and publishes its power, cooling, fiber, and delivery plan.
Capital Partner	GI Partners	Public reporting identifies GI Partners with Legacy on the current conversion ownership and development team.
General Contractor	ARCO/Murray	Named on issued Chicago permit 101084518 as the general contractor.
Architect of Record	Christopher Krestel / C+K Architecture	Christopher D. Krestel is the architect named on the Phase 2 and Phase 3 permits; C+K documents mission-critical design experience.
Electrical Contractors	ABCO Electrical Construction; Bonus Electric; Kelso-Burnett	All three appear on the Phase 3 permit. The record does not divide their package boundaries.
Utility	ComEd	Phase 2 routes distribution from the ComEd vault to upper floors; future expansion beyond 33 MW depends on additional utility capacity.

Low Voltage Systems Breakdown

Legacy's published Chicago Byte Exchange facility brief gives the strongest technology clues: eight carriers on site, dark-fiber and transport access toward 350 E Cermak, 0.5-millisecond round-trip latency to that carrier hotel, and cooling designed for direct-to-chip deployments. Those facts make backbone topology, diverse entrance paths, documentation, and coordinated commissioning more important than a generic office-to-data-center label suggests.

System	Category	Phase 3 Planning Scope	Complexity
Structured Cabling	Data / Voice	High-density copper and fiber-support pathways for data halls, operations spaces, carrier rooms, building systems, and out-of-band management. Existing-building routes must be reconciled with reinforced floors and new MEP distribution.	High
Fiber Optic	Data / Voice	Diverse building entrances, meet-me-room distribution, vertical backbone, carrier handoffs, and test documentation. Eight on-site carriers increase cross-connect volume and change-management requirements.	Very High
Access Control	Security	Layered access from perimeter and loading areas through operations zones, electrical and mechanical rooms, data halls, and tenant cages. Credential policy and audit retention must follow the operator's standard.	High
CCTV / Video Surveillance	Security	Documented coverage across entrances, service routes, critical rooms, circulation paths, and tenant boundaries, with storage sized to the owner's retention policy.	High
Distributed Antenna System	Wireless	Coverage planning through dense reinforced concrete and equipment-heavy floors. Public-safety and carrier requirements must be confirmed before any DAS scope is treated as firm.	High
Audio / Visual	Operations	Operations-center displays, conference and incident rooms, and controlled monitoring interfaces. The public record does not identify an AV package or operator-furnished boundary.	Medium

Two likely data-center systems are intentionally not added to the six-system count. Phase 3 includes MEP equipment, but no public package record reviewed here identifies Building Management System or Electrical Power Monitoring System scope. Likewise, the permit references fire-protection work without proving a Fire Alarm or VESDA specialty award. Contractors should ask for the controls responsibility matrix, point lists, alarm hierarchy, smoke-detection basis, and system-to-system commissioning plan.

Estimated Low Voltage Value

For a reported data-center construction value, LVN's benchmark uses 6% of construction cost and applies a 1.15 coordination multiplier for five or six systems. Applied only to the $151,112,046 Phase 3 permit, that produces an estimated $10.43 million low-voltage planning floor. This is a benchmark, not a bid tab, subcontract award, or representation that every tracked system sits inside one package.

Phase 3 Reported Construction Value	$151,112,046
Data Center Construction Benchmark	6%
Six-System Coordination Multiplier	1.15x
Phase 3 LV Planning Floor	$10,426,731
Broader Program Cross-Check	$12 million to $16 million, using 4% of a reported $300 million to $400 million full conversion
Capacity Cross-Check	$16.5 million, using 33 MW at the conservative national $500,000-per-MW planning anchor

The cross-checks explain the boundaries. Bloomberg's project reporting places the full retrofit at $300 million to $400 million; 4% of that announced program is $12 million to $16 million. Separately, 33 MW at $500,000 per MW produces $16.5 million. Those two full-facility methods converge, while the Phase 3 permit method stays lower because it prices one issued construction phase.

Contractors should carry the $10.43 million figure as the permit-based floor and use the wider $12 million to $16.5 million program checks only when their pursuit includes work outside the Phase 3 boundary. Compute hardware, tenant network electronics, carrier services, and owner-furnished platforms are excluded. The tenant technology standard and commissioning documentation also remain unconfirmed in primary owner material reviewed for this spotlight.

Skills and Certifications Required

Discipline	Useful Credentials	Critical Execution Skills
Structured Cabling	BICSI INSTC, TECH, RCDD	Pathway takeoff, rack elevation coordination, copper certification, labeling, change control, and as-built documentation
Fiber Optic	BICSI INSTF, TECH, RCDD	OSP and riser splicing, OTDR and OLTS testing, polarity control, diverse-path verification, and carrier handoff management
Access Control	State/local registration as applicable; manufacturer training	Door hardware interfaces, fail-safe/fail-secure coordination, elevator and cage access, audit trails, and network segmentation
CCTV	Manufacturer VMS training; Network+	Coverage design, PoE budgets, storage calculations, analytics commissioning, privacy masking, and retention validation
DAS	RCDD; RF engineering and carrier training	RF survey, propagation modeling, donor and head-end coordination, fiber distribution, acceptance testing, and AHJ/carrier closeout
AV / Operations	AVIXA CTS-I or CTS-D	AV-over-IP, control integration, operations-room ergonomics, failover planning, and user acceptance testing

Entry-level technicians can support pathway installation, device mounting, cable placement, labeling, and supervised termination. Mid-level crews must own fiber testing, copper certification, rack quality, and room-by-room closeout. Senior staff need to coordinate carrier demarcations, owner standards, security partitions, commissioning scripts, and the responsibility matrix that separates BMS, EPMS, life safety, security, and tenant systems.

This is a vertical retrofit, so logistics are part of the technical scope. Reels, racks, lifts, and prefabricated assemblies must reach upper floors through an occupied downtown site with finite loading and elevator access. Every penetration needs a documented firestop system, and backbone growth capacity has to be designed before pathways close—not improvised after tenant turn-up.

Market Signal

Chicago Byte Exchange is a clean example of office-obsolescence turning into digital infrastructure. The former trading-floor geometry already offered high ceilings, broad spans, and substantial legacy utility infrastructure. That does not make the conversion simple; it changes the difficulty from greenfield site work to vertical distribution, structural reinforcement, equipment logistics, live utility sequencing, and exact documentation inside an existing shell.

The carrier story is equally important. The site sits near Chicago's established Cermak carrier ecosystem, and Legacy markets eight carriers plus dark-fiber options. In a colocation facility, that density creates more entrance pathways, cross-connect governance, customer-cage security, and audit requirements than a single-tenant enterprise data center. The valuable contractor is the one who can prove diversity, labeling, test results, and turnover—not merely pull cable quickly.

Regulatory timing also matters. GrayStak's review of Chicago's pending data-center measures notes that the LaSalle conversion received its July and September building permits before the September 23 filing date used in proposed moratorium language. The city declined to apply the proposals to this named project, so the article does not call the facility legally exempt. It does show why issued permits have commercial value: entitlement and timing risk are materially lower than on a press-release-only campus.

For business development, the near-term door is the current delivery team. ARCO/Murray and the three named electrical contractors already control real interfaces on an issued permit. A credible approach should lead with mission-critical references, available commissioning capacity, fiber-test standards, security integration experience, and a willingness to work inside the team's existing package boundaries. Generic “we do low voltage” outreach will die in the lobby. As it should.

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