IBM is installing almost 2,000 Macs per week as part of the Mac@IBM program that commenced earlier this year.
Big Blue now has more than 30,000 Macs within its fleet, Apple's CFO Luca Maestri said in the company's earnings call, according to a transcript from Seeking Alpha.
While Macs tend to be considered a high-end choice, Maestri said IBM was saving US$270 compared with a traditional PC, "thanks to the much reduced support cost and better residual value".
"This is a terrific example of the kind of opportunity our devices offer to improve user experience and create value in the enterprise world."
IBM is expected to eventually deploy up to 200,000 Macs per year. The deployment program follows Apple and IBM's partnership in the mobile space, with IBM building enterprise-centric apps to help Apple carve out market share in the corporate world.
IBM is also reselling Macs to enterprise customers.
Apple published its 2015 results overnight, with full-year revenue of US$234 billion, up 28 percent year-on-year. Net profit for the full 12 months was US$53 billion – a margin of 22.6 percent.
Enterprise sales represent an increasing part of the mix, with Apple chief executive Tim Cook revealing enterprise business had grown 40 percent in the past year to crack US$25 billion.