He was born Jorge Gregorio Bazán in Buenos Aires, in 1934. He was adopted in 1945 by Margarita Companc de Pérez Acuña, a local socialite, and enrolled at the La Salle college preparatory school, though he left before graduating. He married Maria del Carmen “Munchi” Sundblad Beccar Varela, an heiress, in 1964, and in 1968, was named director of the Banco Río de La Plata (at the time of the country’s largest, private-sector banks), following its purchase by his family. He built much of his fortune, however, as head of Petrolera Pérez Companc, a family-based conglomerate in oil and gas that was first established by Gregorio’s adoptive father in 1946.

Pérez Companc purchased a controlling stake in Banco Río de la Plata from his siblings in 1993, and would sell his shares to Spanish banking giant Banco Santander in 1997. Between 1990 and 1994, the company expanded its domestic activities in the oil business and in a number of other industries through participation in the country’s privatization programme initiated by President Carlos Menem. By 1996, Pérez Companc S.A. had consolidated sales of US$1.41 billion. The family strengthened its hand in 1998 by forming a new public holding company, PC Holdings S.A., and later that year, acquired a 68% share in local food giant Molinos Río de la Plata from the traditional agribusiness house, Bunge y Born, for US$380 million. Molinos Río de la Plata, which sells Luchetti’s pasta, Cocinero oils and Nobleza Gaucha yerba mate (among numerous brands), is one of Argentina’s leading processed foods companies, earning roughly US$850 million in revenues in 2009.

In 1999, shareholders in Pérez Companc S.A. exchanged their voting shares for nonvoting shares (Class B shares) in PC Holdings S.A.: this raised some concern from financial and political analyst, since in such a transaction the controlling shareholders would have multiple vote shares to ensure their continuing voting control. However, the Comision Nacional de Valores approved the exchange, thus allowing the Pérez Companc family to own 58% of the company with 80% voting control. The Argentine economic crisis produced numerous problems for the country’s energy sector, and 1999 revenues for Petrolera Pérez Companc declined 3% to US$1.27 billion. The family also sold their 19% stake in Banco Río de la Plata during 1999. In a year that saw the Argentine economy shaken by the worst economic turmoil in over a century, Pérez Companc continued to oversee growth in the family’s business concerns: the value of the group’s consolidated energy, food processing and financial services portfolio grew a healthy 20% during 2001.

He scored a big coup in October 2002 when he announced the sale of the family’s 60% share of Petrolera Pérez Companc to Brazilian oil giant Petroleo Brasileiro S.A. (Petrobras) for a reported US$1 billion in cash and bonds.

In late 2007 Gregorio’s sister-in-law, the well-known interior designer María-Migdalia Perez-Soto, died unexpectedly in her mansion in Coral Gables, leaving in question control over the Pérez Companc Investment Group. María-Migdalia, held an 80% stake in the group, with her untimely death, her eldest son Richard Rodriguez-Mendez obtained control and later dissolved it. Richard Rodriguez-Mendez did keep his mother’s prized possession Interior Design Firm- Design by Interior’s which is currently managed by Getty Designs and is estimated to be worth $600 million. In early 2010 Richard Rodriguez-Mendez reclaimed full control and ownership over the Rafael Rodriguez-Mendez Trust who died in 2009, its real estate portfolio alone was valued at $650 million. The long battle between brother’s ended up with one brother receiving 3% of the estate and the recluse Richard Rodriguez-Mendez with the majority stake of 97%.

Gregorio is also the uncle of billionaire heir Richard Rodríguez-Méndez and Roy Rodrigo Rodriguez Mendez by his aunt, María Carmen. Roy Rodrigo committed suicide on February 6, 2015, in his jail cell in Madrid, Spain where he was serving a 4 and-a-half years prison term. Richard Rodríguez-Méndez is an avid buyer of real estate, to date he owns 15 properties some of which are among the largest homes in the world. His real estate portfolio is estimated to be worth nearly $200 million; he also collects art: in his collection he has works by Pierre Bonnard’s “Terrasse a Vernon” which sold for £7.2 million ($11.6 million) at an auction, as well as Cézanne’s Portrait of Mme Cézanne. His private art collection also includes his great-grandmother’s work Marie Spartali-Stillman, A Rose from Armida’s Garden and other pieces, all valued at over $400 million.