IBM has sent a memo advising 20,000 technical staff to move from Microsoft Office to productivity software from its Lotus subsidiary that conforms to open standards.
The memo from IBM's chief information officer, Mark Hennessy, and vice-president Gina Poole was sent to employees yesterday, and although it does not explicitly mention Office, it refers to "a new, more integrated approach to desktop productivity software" that is facilitated by using Lotus Symphony.
Last year, Microsoft attempted to fast-track its Open XML format for standardisation by the International Organisation for Standardisation (ISO), but IBM lobbied hard against it.
A competing standard, Open Document Format, achieves the same task of separating the information from the software creating it and is backed by IBM, Google and others.
Last week, ISO said the process had been stalled following objections from Brazil, India, South Africa and Venezuela.
Although Microsoft would suffer little financial effect even if all 20,000 IBM workers switch to Symphony, the IBM move hints at software trends.
Despite being one of the world's largest technology companies with more than 380,000 staff, IBM has become adept at adapting to new trends in recent years and is a strong supporter of open software standards.