The US consumer packaged goods giant purchased Weetabix Food Company from Shanghai-based Bright Foods and private equity firm Baring Private Equity Asia for approximately £1.4bn ($1.76bn) in April 2017.
It beat off competition from the likes of Nestle, PepsiCo and General Mills to make the acquisition.
The Shredded Wheat and Honey Bunches of Oats maker funded the purchase with existing cash and proceeds from a $1bn incremental term loan facility it completed on June 29, 2017.
The Post Holdings acquisition is the fourth takeover since it was formed in 1932.
In 2016, Weetabix sales were down 2% to £346.4m ($448.70m), while profits dropped 13% to £94.3m ($122.15m).