[1] In July 2005, Zions Bancorporation announced that it would buy Amegy Bancorp for $1.7 billion in cash and stock.

[7][8] Five Post Oak Park, originally developed by The Winter Company, was completed in 1982.

Prior to 1996 Amegy Bank had its headquarters in the three-story, 57,000-square-foot (5,300 m2) ICA Center, which is across the street from Five Post Oak Park.

Amegy Bank leased almost all of the space in the building, which was owned by the Insurance Corporation of North America.

In 1996 Amegy decided to switch places with Heritage Bank, which leased in Five Post Oak Park.

The bank initially leased five floors and placed signs on both sides of the building and on the ground level.