Giving new purpose to a modernist gem

In 1971, SOM, Wurster, Bernardi & Emmons, and consulting architect Pietro Belluschi collaborated to design 345 Montgomery, the flagship banking hall for Bank of America. Situated on a sloped site in San Francisco’s financial district, the building shares a plaza with 555 California Street, originally designed as the bank’s global headquarters. Conceived in the tradition of the grand retail banking hall, yet executed in a distinctly modernist key, the building features a red Carnelian granite facade with glass windows that offer passersby a view of the soaring interior space.

More than four decades after the building’s completion, as digital banking reshaped financial institutions, SOM was commissioned to reimagine 345 Montgomery to serve new uses. The renovation achieves a harmonious balance between honoring the past and embracing the future.

The building currently houses the Institute of Contemporary Art San Francisco, a non-collecting museum that explores social, political, and cultural themes through art. The nonprofit arts organization champions local and international artists, working to dismantle barriers in exhibition practices and advocate for equitable compensation. The project highlights the transformative impact of SOM’s design in supporting a thriving arts institution and fostering a creative environment for artists worldwide.

Renovation and reinvention

The design team took great care to preserve existing materials and to harmonize the renovation with the building’s modernist expression. The redesign preserves the exterior’s stone-encased structural elements, keeping them concealed beneath the original red Carnelian granite facade. Custom storefronts now enhance all four entrances, featuring clear-glass windows framed in aluminum trim, offering pedestrians a seamless view into the interior from the street. High-performance windows, reaching up to two stories in height, were installed near the top of the building, offering expansive city views and enriching the interior experience.

Reimagining interior space with flexibility in mind

The design team refined the interior atrium by clearing its center, adding an upper floor, expanding the third floor, and inserting a central staircase system to connect all levels. This redesign converted the existing three-story atrium into a versatile five-story space capable of accommodating diverse uses. The improved atrium channels sunlight to illuminate the interior, reaching below grade into the basement. Soft oak wood paneling wraps the atrium, complemented by concrete structural piers and dark bronze handrails that provide visual contrast. Oak accents a large ground-floor staircase leading to the basement, where integrated seating transforms the steps into a social gathering space.

Four reinforced concrete piers frame the atrium’s perimeter, stretching from the top floor to the basement and integrating seamlessly with the building’s existing foundation. These piers enhance structural integrity and strengthen the building’s ability to withstand earthquakes.

Two perforated, metal-clad service towers were introduced to house the elevators and restrooms, providing essential vertical circulation. The elevators connect all floors to the ground level at Montgomery Street, the above-grade plaza fronting the 555 California tower, and the pedestrian concourse beneath the plaza.

The existing ceiling, a sweeping architectural lighting feature preserved during the renovation, displays a uniform array of illuminated cubes that brighten the entire building. Above it, an advanced fire safety system was installed, utilizing a sophisticated fan mechanism to draw smoke and hot gases upward while circulating clean air below to provide for safe evacuation.