Rational specialises in providing a structured development environment, the Extended Development Experience (XDE), that suits the complex projects undertaken by multinationals and large corporates, many of which are also IBM customers.
The two companies have had a close relationship since 1985 and analysts are not predicting any major problems for current customers or for the integration of Rational into IBM.
Bola Rotibi, Ovum's lead analyst for software and development strategies, said that the deal gives IBM an opportunity to provide a more integrated development environment than it has had in the past. "It gives IBM customers the ability to model and test their projects but it may also bring some positive results on lower costs as IBM positions XDE and the Rational Rose Java environment as its flagship development products."
Dennis Gaughan, research director at AMR Research, described the takeover as unheralded, or "coming out of the left field".
"This has led to speculation that IBM moved to pre-empt any attempt from Microsoft to buy Rational," he said.
The acquisition is due to be completed early next year.