The deal will enable St Ives, which already supplies clients with marketing support services, to bolster its data-marketing capabilities.
Bristol-based Occam employs 80 people and has an £8m turnover. Following the deal, its data services will be used by the printing group's St Ives Direct division, which already provides customers with direct mail print and targeting services.
Patrick Martell, St Ives' chief executive, said: "Occam is an excellent fit with our existing businesses. By combining data services with St Ives print, digital print, direct mail, email and SMS services, we will offer a compelling proposition to our customers."
He added: "Managing customers' data more effectively, providing insight and combining this with media production to maximise return for our customers, is now a reality."
The debt-free £12m sale price, which will be paid through a combination of cash and St Ives shares, could be upped to £12.6m, .
As a result of the deal, Occam will become a wholly owned subsidiary of St Ives and its senior management team, including managing director James Bagan, will remain in place.