Sullivan & Cromwell, Simpson Thacher & Bartlett and Latham & Watkins are playing lead roles in the planned merger of financial services technology provider Fiserv and First Data Corp., a leading processor of credit and debit card transactions.

The deal, an all-stock transaction, has a projected equity value of $22 billion. Under the deal's terms, Fiserv will acquire First Data, whose shareholders will receive 0.303 Fiserv shares for each unit of First Data common stock they hold. Fiserv shareholders will come away from the deal with ownership of 57.5 percent and First Data shareholders with 42.5 percent of the new entity.

In a statement about the merger, Fiserv said it will refinance the roughly $17 billion of debt that First Data will shoulder at the time the deal closes.

A team from Sullivan & Cromwell, led by corporate partners Mark Menting and Jared Fishman; finance partners John Estes and S. Neal McKnight; executive compensation partner Matthew Friestedt; tax partner David Spitzer; and intellectual property partner Nader Mousavi, is advising Fiserv.

Simpson Thacher is advising First Data. Its team includes M&A partners Elizabeth Cooper, Gary Horowitz and Kathryn King Sudol; capital markets partner Richard Fenyes; banking and credit partner Daniel Kay; executive compensation and employee benefits partner David Rubinsky; intellectual property partner Lori Lesser; and tax partner Rob Holo. The firm comes to the deal with significant knowledge of the company, having advised it on its $2.5 billion IPO in 2015, the biggest IPO that year. It also previously represented KKR in its $29 billion acquisition of First Data in 2007.

Latham & Watkins, which is representing First Data's board of independent directors, also has experience with the parties involved. In 2013, Latham advised the Carlyle Group on the $55 million sale of Open Solutions to Fiserv, a deal whose real value was reportedly $960 million when taking debt into account. Latham partners Peter Harwich and Charles Ruck are advising First Data's board.

Kirkland & Ellis is serving as counsel to New Omaha Holdings, a KKR affiliate holding about 39 percent of First Data's outstanding common stock and 86 percent of First Data voting rights. The Kirkland team includes corporate partners Sean Rodgers, Ravi Agarwal and Benjamin Leyendecker, and capital markets partners Joshua Korff and Ross Leff.

Fiserv is receiving financing for the merger from its financial adviser, JPMorgan Securities. First Data's financial adviser is BofA Merrill Lynch. Evercore is acting as financial adviser to First Data's board of independent directors.

After an unusually robust year for M&A in 2018, the Fiserv-First Data merger comes on the heels of another high-value merger announced in January, Bristol-Myers Squibb's $74 billion acquisition of Celgene Corp., ushering in what looks to be another strong year matching or outpacing 2018.