The transaction adds £16 million of revenues to 6DG's hosting portfolio. BIS also adds 200 customers and 30 people to 6DG, taking the total group headcount to 250 staff after other recent acquisitions.
Six Degrees Group was established in June 2011 with £60 million of venture capital funding. It has now acquired 13 different companies since then.
Alastair Mills, CEO of Six Degrees Group, said, "To serve both our City clients and mid-market customers across the UK, a central London datacentre presence is critical.
"BIS adds huge credibility to our service offering. Many of our target customers still insist on a proprietary London presence and not just reselling space in somebody else's data centre which, frankly, anyone can offer."
The value of the BIS acquisition has not been disclosed.