The days of referring to the leading management software vendors as the "big four" are numbered, industry watchers predict, as challengers to BMC, CA, HP and IBM now include a variety of competitors from starts-up to software giants such as Microsoft and Oracle.

Forrester Research recently released a paper that advised IT executives on optimizing their current IT management software portfolio. While a majority of companies have multiple management products in house, at least one of four names is likely to dominate customer portfolios: BMC, CA, HP and IBM. Forrester advises IT executives to employ a management strategy that would designate one vendor as an "anchor" and then fill technology gaps with others. HP and IBM would be likely anchors, but the report reveals BMC and CA might not be able to fill that role going forward.

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"HP and IBM are so massive that they will likely survive an assault on their business, but BMC and CA are the smallest mega-vendors and are therefore a bit more vulnerable to business fluctuations and acquisitions," says Glenn O'Donnell, a senior analyst with the firm.

BMC and CA don't have the hardware or services business that HP -- more so now with its EDS acquisition final -- and IBM do. "Oracle, the formidable wild card, is a minor management vendor now, but it will acquire leadership in its typical bold manner. Either BMC or CA is the likely prey," O'Donnell says. "Oracle must become a significant leader in management, as this business represents a key element of its overall business automation strategy."

Microsoft has been a strong contender in managing its own environment, but recent technology developments such as virtualization and upgrades to its Systems Center package are broadening its heterogeneous management and operational automation products.

"With its competition migrating away from the Linux/Java world and toward Google, we expect Microsoft to keep momentum moving toward heterogeneous environments," O'Donnell says. 'It will be a solid anchor and also a stronger force in the whole IT automation movement. Whichever is not consumed by Oracle will be fodder for Microsoft's ambitions."

CA, in particular, would be an attractive acquisition for the two software makers. Recent technology developments and dedication to building its customer base has the vendor making points with the analyst community and earning respectable customer satisfaction reviews.