STACK's MIL01 campus sits on Via Marche in the Siziano industrial zone, in the province of Pavia, about 15 km south of central Milan. The fenced lot covers about 10 hectares beside the SP40 Binasco-Melegnano road.
Ownership history
SUPERNAP Italia chose Siziano in 2015 for its highway access, low seismic risk and a nearby Terna high-voltage substation. Construction started in July 2015. IPI Partners bought SUPERNAP Italia in 2021 and rebranded it STACK EMEA in 2022. In 2025 STACK sold its European enterprise colocation business to Apollo-managed funds. That business now runs as Vaultica and sells colocation on the campus. STACK kept the buildings and its hyperscale customers. STACK's other Siziano data centers sit on separate lots nearby.
Infrastructure
- Dedicated on-site high-voltage substation, fed by two 132 kV transmission paths.
- Diesel standby generators at each building, with fuel for up to 80 hours.
- Rooftop and canopy solar panels, plus renewable power purchases.
- More than 200 dedicated fiber pairs on diverse paths to the Milan Caldera campus and the MIX internet exchange.
- ANSI/TIA-942 Rating 4 construction certification.
Milestones
- 2015: Construction starts.
- 2016: Campus opens as SUPERNAP Italia.
- 2021: Second building opens; IPI Partners buys SUPERNAP Italia.
- 2022: Rebranded STACK.
- 2025: Third building finished; STACK sells its colocation business to Apollo funds, which run it on the campus as Vaultica.