Benzinga's M&A Chatter for Wednesday December 21, 2011

Here are the M&A deals and chatter for Wednesday December 21, 2011.

reported them in real-time as they occurred:

: WCA Waste Corporation

announced Wednesday that it has entered into an agreement and plan of merger with Macquarie Infrastructure Partners II. Under the terms of the agreement, MIP II will acquire all of the outstanding common stock of WCA for $6.50 per share in cash, redeem all Series A preferred stock and either partially or completely refinance WCA's existing credit facilities. The transaction is valued at approximately $526 million. The purchase price represents a premium of 30% over WCA's closing stock price on December 20, 2011. Shares of WCA Waste Corporation traded in a range of $4.76 to $4.95 during the regular session Wednesday on twice of the average daily volume, closing at $4.91. However, trading was halted at 4:00pm shortly before the deal was announced. WCA traded at $6.37 once trading resumed at 4:35pm, a gain of 30%.

: Tokio Marine Holdings (TKOMY) and Delphi Financial Group

announced Wednesday that they have entered into a definitive agreement under which TMHD will acquire all outstanding shares of Delphi, a leading financial services holding company comprised of specialty life and property & casualty insurance and insurance-related businesses, for $43.875 per Class A share and $52.875 per Class B share in cash, through TMHD's wholly owned subsidiary, Tokio Marine & Nichido Fire Insurance Co. In addition, Delphi shareholders will receive $1.00 in cash per share pursuant to a one-time special dividend from Delphi for each share of Class A and Class B stock they own. The total transaction value is approximately U.S. $2.7 billion and is expected to close in the second quarter of 2012. Shares of Delphi Financial Group traded in a range of $43.81 to $44.00 Wednesday on 33 times the average daily volume and closed at the high of the day for a gaon of 73%.

: CBIZ

announced Wednesday that it has acquired the actuarial and retirement plan consulting business of PSA Insurance and Financial Services of Hunt Valley, MD, effective November 1, 2011. The actuarial and retirement plan consulting book of business recorded approximately $1.2 million in revenue during the past twelve months and includes four associates servicing the business. Shares of WCA Waste Corporation traded in a range of $5.94 to $6.09 Wednesday on slightly less than the average daily volume and closed at $6.05, a gain of 0.50% for the day.

: The U.S. Department of Justice Wednesday cleared the way for the merger of Exelon Corporation

and Constellation Energy

, in connection with its review of the transaction under the Hart-Scott-Rodino Act. Consistent with Exelon's merger application to the Federal Energy Regulatory Commission, in these papers, the company makes a number of commitments to mitigate market power concerns, including: divestiture of certain assets, granting DOJ the right to approve the buyers of those assets, assurances about how the merged company will bid its units into the PJM markets pending divestiture, and deadlines for the sale of those assets. Shares of Constellation Energy, briefly halted on a circuit breaker, traded in a range of $35.04 to $39.63 on 4.7 times the average daily volume and closed at $39.60, a gain of 2.86% for the day. Shares of Exelon Corporation, traded in a range of $41.88 to $43.44 on 2.5 times the average daily volume and closed at $43.38, a gain of 2.48% for the day.

: Microsoft

will acquire Research in Motion

, according to comments out of Jefferies on Wednesday. This rumor has been resurfacing over the past two years as one of several possible smartphone acquisitions by Microsoft. RIMM shares got a boost from the chatter and rose 10% Wednesday on 3.4 times the average daily volume. Research in Motion traded in a range of $13.26 to $14.14 and closed at $13.78.

: Cisco

to acquire JDS Uniphase

for $13.50 per share. Another tech name that circulates among trading desks from time to time. JDS Uniphase shares traded in a range of $9.53 to $9.86 Wednesday on half the average daily volume and closed at $9.80, a loss of 1% for the day.

: Yahoo

to sell most of its stake in Alibaba (

) and Yahoo Japan, according to sources reported by the New York Times. Yahoo's Board of Directors is scheduled to meet Thursday to discuss the proposal, which would sell the assets back to Alibaba and Softbank. Yahoo would retain a 15% stake in Alibaba. Shares of Yahoo traded Wednesday in a range of $14.74 to $16.24 Wednesday on 64% greater than the average daily volume and closed at $15.99, a gain of almost 6% for the day.

: Roche (

) to acquire Inhibitex

for $25 per share. The rumor first surfaced on Monday. Shares of Inhibitex traded in a range of $10.50 to $11.88 Wednesday on 40% more than the average daily volume and closed at $11.21, a gain of 6.5% for the day.