The agency replaces Countrywide Porter Novelli, which has managed the account for the last year, but declined to repitch.
BMC, which was founded in 1980 in Houston, Texas, has an annual turnover of just under £1bn.
Kaizo will handle media relations, targeting trade magazines and the national press.
Account director Louis St Claire, who heads a team of five, said: ‘We’ll be focusing on The Guardian and The Financial Times, as well as weekly and monthly IT and business publications.’
BMC marketing director Sarah Atkinson said: ‘For too long, there has been a gap between IT and businesses. Through this campaign, we’re hoping to link the two.’
Kaizo scooped researcher NOP World’s PR account in March (PRWeek, 28 March).