The scheme – which is home to 80,000 sq ft of retail and leisure space – is being marketed by property agency JLL, Business Live has reported.
Mailbox – which also comprises office space and apartments – is home to retail tenants including Tesco Express, Harvey Nichols, and James Lakeland.
In total the scheme comprises some 1.07 million sq ft of space across 6.2 acres.
Mailbox is also the current headquarters of BBC Midlands, although the broadcaster is set to move to The Tea Factory, also in Birmingham, by 2026.
According to a marketing brochure, the complex currently has an annual rental income of £12m, and a vacancy rate of 4.6%.
It reads: “The Mailbox is exceptionally well let, with a very low vacancy rate and benefits from significant asset management, value add and repositioning options in the immediate and longer term.
“The Mailbox offers an established workplace and lifestyle ecosystem, with a balanced mix of office, leisure and cinema, retail and department store and car park uses.”
The building’s owner, Mailbox REIT, recently delisted from the International Property Securities Exchange (IPSX) after the market announced it would be closing down the end of the year. Mailbox REIT said it does not intend to list itself on another exchange.