How the 'White Box' Premium and Tenant Improvement Allowance Dictate the Value of an Unfinished Luxury Penthouse

On the top floor of the 16-story Embry tower in Chicago's West Loop, a buyer recently stood on a bare concrete slab surrounded by exposed plumbing stacks and floor-to-ceiling glass. They paid $5.25 million for the 5,200-square-foot space—not for a finished home, but for a "white box" shell. The transaction, which cleared $1,009 per square foot for raw space, illustrates a structural shift at the apex of the luxury housing market.[4]

A "white box" penthouse is delivered with only the structural and mechanical elements in place. In both price and desirability, these units represent real estate's most literal expression of the top tier. Forbes reported in April 2026 that a current trend in penthouse design is the white box: "clean, blank canvases that inspire potential buyers to be creative with their personal tastes and design."[1]

In the commercial real estate sector, delivering an unfinished space is standard practice, but the economics are entirely different. Commercial build-outs are typically governed by a Tenant Improvement Allowance (TIA). According to Cushman & Wakefield, a TIA is a "pre-negotiated sum of money provided by the landlord or owner of the building to the tenant" that covers all or a portion of the construction costs needed to fit out the space.[3]

The allowance is usually expressed as a per-square-foot amount, allowing the commercial tenant to customize the space while the landlord retains control over the building's long-term value. Spacebase notes that these improvements are "most often paid for by the landlord" because the owner will retain the long-term value of the permanent modifications, such as new walls, flooring, and HVAC systems.[2]

However, in the ultra-luxury residential sector, this dynamic flips completely. Buyers are purchasing the white box outright, assuming the full capitalization risk of the build-out without a landlord's allowance to offset the costs. The premium paid for unfinished space reflects the value of absolute customization, allowing the buyer to dictate every detail from the floor plan to the finishes.[1][6]

The financial commitment extends far beyond the initial purchase price. For the 5,200-square-foot shell at the Embry tower, The Real Deal noted that a "low-ball" build-out estimate of $200 per square foot would add over $1 million to the final cost basis. In reality, ultra-luxury finishes often push construction costs well beyond that baseline.[4]

High-end buyers typically bring in their own architects and interior designers to shape the layout. This includes determining the placement of non-load-bearing walls, routing custom HVAC zones, and installing specialized infrastructure like art gallery lighting or heavy-load flooring for large sculptures.[1][6]

This decoupling of the shell's value from the interior finishes fundamentally alters how these properties are appraised. Without standard comparables for finished interiors, appraisers must evaluate the raw square footage, the panoramic views, and the exclusivity of the building's amenities, such as private elevators and wrap-around terraces.[1][6]

The tax implications also differ significantly from commercial TIAs. While commercial landlords can amortize the cost of a TIA over the life of the lease, residential buyers must capitalize the build-out costs, adding them to the property's cost basis. The Internal Revenue Service outlines strict rules for depreciating residential rental property improvements, but for owner-occupied penthouses, these costs are only recovered upon the eventual sale of the asset.[5][6]

The white box model also shifts the timeline for occupancy. Buyers must navigate complex permitting processes, material sourcing, and construction delays, often pushing their move-in date back by 12 to 18 months. For the ultra-wealthy, this delay is considered a necessary trade-off to achieve a truly bespoke residence.[6]

Developers are increasingly embracing this strategy. By selling the shell, they eliminate the risk of choosing finishes that might alienate a prospective buyer, while simultaneously reducing their own upfront construction costs. Sulo Development, the firm behind the Embry tower, successfully utilized this approach to set a high price point for the West Loop neighborhood.[4][6]

Despite the hurdles of managing a multi-million-dollar construction project, the demand for blank-canvas penthouses continues to rise in gateway markets. Driven by a clientele that views turnkey finishes as a compromise rather than a convenience, the white box premium is cementing its place as the ultimate luxury commodity.[1][6]