In a brief but combative television address to the nation, Mr. Temer contended that the billionaire who secretly taped their discussion about obstructing graft inquiries had profited immensely from insider trading in the days before the recording was made public.
“He committed the perfect crime,” Mr. Temer, 76, said about Joesley Batista, 44, the heir to the JBS global beef empire, accusing him of lucrative trades in futures markets after negotiating a plea deal with investigators.
Reports about the negotiations sent shock waves through Brazil’s financial markets in recent days as uncertainty gripped the country over renewed political turmoil, potentially creating a windfall for some investors.
The aggressive positioning by Mr. Temer, who called Mr. Batista a “notorious exaggerating windbag,” raises the stakes in the political impasse engulfing Brazil.
Calls for the president to resign have intensified in recent days since Brazil’s prosecutor general said Mr. Temer was facing an investigation into claims he received millions of dollars in illicit payments and sought to obstruct an anticorruption drive.
Mr. Temer argued on Saturday that efforts to restore economic stability in Brazil were at stake if his government fell. Mr. Temer rose to power just a year ago after a bitter power struggle resulting in the impeachment of his leftist predecessor, Dilma Rousseff.
Regarding the accusations of Mr. Batista’s trades, Brazil’s securities regulator said Friday night that it was investigating alleged irregularities by JBS including the possible crime of “insider trading.” JBS said in a statement that its trading activities were legal.
Mr. Temer also claimed on Saturday that Mr. Batista’s recording of their meeting one evening in March at the president’s residence in the capital, Brasília, had been “manipulated and adulterated.” Mr. Temer emphasized that he was issuing a request to the Supreme Court to suspend the investigation around Mr. Batista’s plea deal.
“This does not reduce the political crisis and does not improve Temer’s situation,” said Paulo Baía, a professor of political science at the Federal University of Rio de Janeiro, describing the president’s strategy as one of trying to disqualify his accuser and the evidence that Mr. Batista provided about Mr. Temer.
“Temer is in intensive care, in a very serious state, trying to survive,” Mr. Baía said.
Indeed, the investigation of Mr. Temer is the most serious crisis of his brief presidency. Allies of Mr. Temer had already been forced to resign over claims they tried to stymie corruption inquiries, but Mr. Temer has shown some success in persuading lawmakers to approve austerity measures aimed at shoring up confidence in the economy.
Mr. Temer himself was already governing under the cloud of scandal, facing testimony that he negotiated in 2010 a $40 million bribe for his scandal-ridden Brazilian Democratic Movement Party. Mr. Temer denies the claims.
But while Brazil’s Constitution prevents a sitting president from being investigated for acts committed outside their mandate, Mr. Temer is coming under intense scrutiny over the latest claims. In Mr. Batista’s recording, Mr. Temer seems to be heard endorsing bribes of a jailed politician who helped orchestrate Ms. Rousseff’s ouster.
Separately, executives at JBS said that Mr. Temer received about $4.6 million in illegal campaign contributions in 2014, when he was vice president on Ms. Rousseff’s ticket, and pocketed some of the money for himself, according to testimony released by the Supreme Court.
Mr. Temer insisted on Saturday that he was innocent of wrongdoing, going on the attack against Mr. Batista. He accused the billionaire, who traveled recently to the United States, of not spending a day in jail despite admitting to an array of crimes.