TPG and the Canada Pension Plan on Thursday announced a deal to buy IMS Health Inc hich provides prescription drug sales data, for around $4 billion.

The $22 a share cash deal could be one of the year's largest leveraged buyouts.

Private equity firms were shut off from striking traditional LBOs after the credit crisis limited access to financing. However, that situation has been improving and deal-flow from private equity firms has been increasing the past few months.

The IMS deal has fully committed financing, consisting of a combination of equity to be invested by TPG and the Canada Pension Plan, and debt financing to be provided by Goldman Sachs.

Shares of IMS, which last month confirmed it was exploring strategic alternatives, soared more than 24 percent to $20.90 in early trading.

(Reporting by Megan Davies, additional reporting by Paritosh Bansal, Pav Jordan and Jessica Hall; Editing by Gerald E. McCormick and Maureen Bavdek)