International Business Machines Corp. announced Sunday its $33.4 billion purchase of open source software company Red Hat Inc. The megadeal, which could change the face of cloud computing, is the largest ever acquisition of a software company and the third-largest ever in the technology sector, according to news reports.

Aside from its size and scope, the tie-up between IBM and Red Hat also has M&A lawyers talking about the outside legal advisers retained to pull off the deal, which both companies do not expect to be completed until the latter half of 2019.

Paul, Weiss, Rifkind, Wharton & Garrison is serving as lead M&A and finance counsel to IBM, while Hogan Lovells is advising the Armonk, New York-based technology giant on antitrust matters. Raleigh, North Carolina-based Red Hat has turned to Skadden, Arps, Slate, Meagher & Flom and Debevoise & Plimpton is representing Guggenheim Partners LLC and Morgan Stanley & Co. LLC in their roles as financial adviser to the target. Securities filings show that Simpson Thacher & Bartlett is working on financing for the deal arranged by JPMorgan Chase & Co. and The Goldman Sachs Group Inc.