Packaging giants Smurfit Kappa and WestRock (NYSE:WRK) have reached an agreement to merge, forming the world's largest publicly traded paper and packaging company, with an estimated value of nearly $20 billion. Following this announcement, WestRock's stock surged more than 8% pre-market today.

In accordance with the merger terms, WestRock shareholders will receive one share in the newly formed entity, Smurfit WestRock, and $5 in cash for each of their existing shares, equating to a total of $43.51 per share.

On the other hand, Smurfit Kappa shareholders will be given one new Smurfit WestRock share for every share they currently hold. This will result in their ownership of approximately 50.4% of the combined company once the merger concludes in the second quarter of 2024.