Energy Corporation of Dallas for US$740 million in 1995. Estenssoro died in a plane crash in Ecuador, where Maxus maintained wells, in May of that year. His policy of high exploration investments was maintained by his successor, Nells León, and reserves expanded by 50% while production rose from 109 million barrels in 1993 to a record 190 million in 1998; of the latter total, 32 million were produced by Maxus operations in Ecuador and elsewhere. Repsol acquisition Madrid-based multinational corporation Repsol S.A. purchased 98% of YPF in 1999 in two stages: a 15% share sold by the national government for US$2 billion, and a further 83% for over US$13 billion including all remaining public sector shares (10%, equally divided between the nation and the provinces) as well as most of the outstanding investor shares. The union of the two companies took on the name Repsol YPF; YPF would represent 40% of the new firm's reserves and over 50% of its production. The Petersen Group (property of the Eskenazi family of Buenos Aires) entered into a partnership with Repsol in 2007 by acquiring a 15% stake in YPF; the group bought another 10% of the company for US$1.3 billion on 4 May 2011. A majority of the firm's shares (58%) remained under the control of Repsol, while 16% remained in private portfolios; the Argentine Government retained the golden share. In 2014, Repsol exited the Argentine market, giving up its stake in YPF. Renationalization Argentine international energy trade recorded an imbalance of US$3 billion in 2011, the first negative figure since 1987, and the relationship between YPF and the government became difficult. Investment in exploration at YPF as a percentage of profits had been far below those in most other Repsol subsidiaries. Market analysts and Repsol blamed the decline in exploration and production on government controls on exports and prospecting lease awards, and price controls on domestic oil and gas. Political risks and government intervention, including price controls, have discouraged foreign investment in oil production in Latin America in general. President Cristina Fernández de Kirchner raised YPF frequently in speeches during March 2012, claiming that underinvestment and excessive dividends at the firm had caused declines in output. Governors in six fossil-fuel producing provinces subsequently revoked YPF leases representing a fifth of its oil production. Citing Brazilian oil giant Petrobras as an example, the president announced the introduction of a bill on 16