Pinnacle Financial Partners (PNFP) and Synovus Financial (SNV) said late Thursday they agreed to merge in an $8.6 billion all-stock deal to form a regional bank focused on the US Southeast market.

Pinnacle Financial and Synovus shares both tumbled 14% on the news.

The new company will operate under the Pinnacle Financial Partners and Pinnacle Bank names. Synovus CEO Kevin Blair will become CEO of the combined firm, while Pinnacle CEO Terry Turner will serve as chairman.

The shares of Synovus and Pinnacle stockholders will convert into shares of a new Pinnacle parent company based on a fixed exchange ratio of 0.5237 Synovus shares per Pinnacle share, representing a Synovus per share value of $61.18, the companies said.

Post-merger, the companies said Pinnacle shareholders will own 51.5% of the new entity, and Synovus shareholders 48.5%.

The merger is expected to close in Q1 2026 and be tax-free for shareholders, the companies said. It is also projected to be 21% accretive to Pinnacle's estimated operating earnings per share in 2027.