Simmons First National in Pine Bluff, Ark., has agreed to buy Landrum Co. in Columbia, Mo. The $17.9 billion-asset Simmons said in a press release Wednesday that it will pay $433.9 million in stock for the $3.3 billion-asset parent of Landmark Bank. The deal, which is expected to close in the fourth quarter, priced Landrum at 175% of its tangible book value. Landmark has 39 branches in Missouri, Oklahoma and Texas. It has $2.1 billion in loans and $3 billion in deposits. Landmark “will fit in our organization perfectly,” George Makris Jr., Simmons’ chairman and CEO, said in the release. Landmark “is a strong banking franchise with deep history and much success in the communities it serves.” Simmons said the deal should be 6% accretive to its 2020 earnings per share. It should take less than three years for Simmons to earn back an expected 3.7% dilution to its tangible book value. Simmons plans to cut about a third of Landrum’s annual operating expenses. The company said it expects to incur about $28 million in merger-related expenses. Stephens advised Simmons. Keefe, Bruyette & Woods advised Landrum.