Bloomberg said representatives from Big Blue held "informal" talks with RIM executives about a potential deal. The news service cited unnamed sources it said were familiar with the discussions.
Berenberg Bank analysts value the unit at between $1.5 billion and $2.5 billion, according to figures cited by Bloomberg. IBM declined to comment.
[ There are a lot of questions about the future of RIM. Read Will Samsung License BlackBerry 10? ]
RIM, once the leader in the smartphone category, has been surpassed by Apple and Google, whose consumer-focused products are gaining popularity with corporate users.
RIM's share of the U.S. smartphone OS market fell 1.6% in June, to 10.7%, according to the most recent data from Comscore. Google's Android platform led the market with a 51.6% share, while Apple was second with a share of 32.4%. RIM lost 37 cents per share in the last quarter.
Earlier this year, RIM revealed that it had engaged investment banks JPMorgan Chase and RBC Capital Markets to help find a buyer or partner. CEO Thorsten Heins has said he prefers the latter option. Previous reports have indicated that Microsoft, which is struggling to establish its Windows Phone brand, has eyed a possible RIM buyout or alliance.
RIM's enterprise unit would allow IBM to add mobile services to its business of managing large companies' computers and data networks. It could also give a boost to IBM's Global Services group, which accounts for more than half of the company's total revenue. The group has seen its top line falter in recent quarters. IBM's technology outsourcing sales fell 2% in the second quarter, while sales of business services were down 4%.
IBM has announced or completed five acquisitions so far in 2012, including a deal in May for customer analytics software developer Tealeaf Technology.
Most observers believe Heins and RIM's board will wait until next year's arrival of BlackBerry 10 before making a decision about the company's future. If the twice-delayed platform, which promises a total revamp of the BlackBerry, is successful, they may attempt to continue running RIM as an independent company.
RIM has shown little of BlackBerry 10 to date. It has demonstrated an interface that allows apps to "flow" from one to the next, and apps that can run in an always-on state so users can pick up where they left off after exiting an application.
Android and Apple devices make backup a challenge for IT. Look to smart policy, cloud services, and MDM for answers. Also in the new, all-digital Mobile Device Backup issue of InformationWeek: Take advantage of advances that simplify the process of backing up virtual machines. (Free with registration.)