Post Holdings (POST) began trading on the NYSE on Jan 27, 2012

Shares of Post Holdings, Inc. began trading  on the NYSE on Jan 27, 2012, under the ticker symbol “POST” after the culmination of the spinoff from Ralcorp Holdings, Inc. (NYSE: RAH)

 

Ralcorp underwent several massive restructurings before ultimately being acquired:

1994 (Public Debut): Formed via a corporate spin-off from Ralston Purina. It began trading under the ticker symbol RAH on the New York Stock Exchange (NYSE)
2007–2008 (Major Brand Acquisition): Ralcorp purchased the major consumer brand Post Foods (makers of Honey Bunches of Oats and Grape-Nuts) from Kraft Foods for $2.6 billion
February 2012 (Post Holdings Spin-off): In an effort to focus entirely on its private-label (store-brand) business, Ralcorp spun off its branded cereal unit into a standalone public company known today as Post Holdings (NYSE: POST)
January 2013 (Final Acquisition): After long corporate negotiations, ConAgra Foods officially acquired Ralcorp for $5 billion in cash (a total transaction value of $6.8 billion including debt), taking the company private. ConAgra later sold off the bulk of Ralcorp's private-label operations to TreeHouse Foods in 2016.