German software giant SAP is buying cloud-based trading network Ariba for 4.3 billion dollars, the companies announced Tuesday. Analysts said the deal would expand SAP's cloud-based offerings and help it compete in the enterprise market with main rival Oracle. The transaction, which represents a 20 % premium on Ariba's closing price Monday, is expected to be completed in the third quarter of 2012, pending approval by Ariba shareholders and government regulators. Based in California's Silicon Valley, Ariba uses cloud-based software to help companies collaborate with partners around the world. Last year, it booked 444 million dollars in revenue and conducted trades worth 319 billion dollars, according to an SAP statement.