Nielsen Holdings NV (NYSE: NLSN) has agreed to acquire Arbitron Inc. (NYSE: ARB) for approximately $1.26 billion, or $48 per share in cash (26% premium to yesterday’s closing price). Major Nielsen shareholders include The Blackstone Group, THL Partners, The Carlyle Group, KKR and Hellman & Friedman.

American Railcar Industries Inc. (Nasaq: ARII) has offered to acquire rival railcar maker Greenbriar Cos. (NYSE: GBX) for approximately $543 million, or $20 per share (5.4% premium to yesterday’s closing price). Carl Icahn controls American Railcar, while last month he reported nearly a 10% stake in Greenbriar.

ConocoPhillips (NYSE: COP) has agreed to sell its Algerian business to Indonesia’s Pertamina for approximately $1.75 billion.

Elliott Management has offered to acquire business software maker Compuware (Nasdaq: CPWR) for approximately $2.3 billion, or $11 per share. That represents around a 25% premium to where Compuware was trading last month before Elliott disclosed that it holds around an 8% stake in Compuware.

Joh. A. Benckiser, a German holding company, has agreed to buy Brooklyn Center, Minn.–based Caribou Coffee Co. (Nasdaq: CBOU) for approximately $340 million, or $16 per share (30% premium to Friday’s closing price).

Cinven is in talks to sell Italian aerospace company Avio SpA for at least $4 billion to General Electric (NYSE: GE), according to the NY Times. Cinven acquired a majority stake in Avio in 2006 from The Carlyle Group and Finmeccanica for $3.3 billion.

Denham Capital has agreed to sell its stake in the GNPower Mariveles project, a 600-megawatt power generating plant currently undergoing commissioning in the Philippines’ Bataan province, to Ayala Corp. The deal is valued at $155 million.

First Reserve Corp. and Trilantic Capital Partners have sold the assets of TLP Energy, an Oklahoma City-based oil and gas producer focused on the Texas Panhandle and Oklahoma, to NFR Energy. The deal was valued at approximately $655 million. NFR is a Houston-based portfolio company of First Reserve Corp. and Nabors Industries Ltd. (NYSE: NBR).

Home Depot (NYSE: HD) has acquired BlackLocus, an Austin, Texas-based provider of data-driven price optimization solutions for retailers. No financial terms were disclosed. BlackLocus last year raised $2.5 million in VC funding from DFJ Mercury and Silverton Partners.

Industrial Opportunity Partners has sold Center Manufacturing, a Byron Center, Mich.-based maker of complex wielded assemblies, to Mayville Engineering Co. No financial terms were disclosed. Quarton Partners managed the process.

Palladium Equity Partners has agreed to sell Wise Foods Inc., a Berwick, Penn.-based maker of snack brands like Wise and Cheese Doodles, to Mexico-based Arca Continental (BMC: AC) for an undisclosed amount.

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