Midday Movers: Rambus Soaring on Split News and Dial Lower on Earnings Warning

Rambus' (RMBS Quote) board approved a 4-for-1 stock split. Rambus jumped 37 17/32, or 9.9%, to 417.

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Three IPO are debuting during today's trading session. For more on their pricing and performance, check out TheStreet.com's Offerings and stock action coverage.

Mergers, acquisitions and joint ventures

CoreComm Limited (COMM Quote), a provider of integrated telephone, Internet and data services to business and residential customers in targeted markets in the U.S., is acquiring ATX Telecommunications Services, a privately held company, for $900 million. CoreComm Limited advanced 6 15/16, or 16.8%, to 48 1/8.

Medarex(MEDX Quote) set a pact with Regeneron(REGN Quote) to create and market drugs based on antibodies. Medarex declined 19 21/32, or 11.8%, to 147 while Regeneron climbed 2 1/8, or 5.2%, to 43 3/16. ...