Clayton, Dubilier & Rice, LLC is in discussions to invest about $1 billion in enterprise software provider Pegasystems Inc. (NasdaqGS:PEGA), according to people familiar with the matter. The investment is strategic for CD&R and not a prelude to a takeover of Pegasystems, said one of the people, asking not to be identified because the matter is private. Terms aren't finalized and the discussions could still fall apart.