SAN FRANCISCO (BLOOMBERG) - Tesla chief Elon Musk asked a judge to let him ignore a request for a deep dive into his financial records from the cave explorer who sued him after they traded insults last year.

Mr Vernon Unsworth wants the records, including a calculation of Mr Musk's net worth, for a defamation trial set to start in December in Los Angeles.

The British caver didn't explain in his subpoena why he's seeking the records.

Mr Musk's lawyers said in a filing on Thursday (Nov 21) that disclosing the information would be "highly prejudicial" to their client and would "inflame the jury".

Besides, they said, Mr Musk already has testified under oath that his net worth is "substantially in excess of US$1 billion (S$1.36 billion)".

"There is no amount of compensatory damages that a jury could properly award Mr Unsworth on his claim, for which any net worth of Mr Musk in excess of US$1 billion would be relevant," they wrote.

According to the Bloomberg Billionaires Index, Mr Musk has an estimated net worth of US$27.3 billion.

Mr Musk and Mr Unsworth locked horns last year after the caver said in an interview on CNN that a mini-submarine Mr Musk had sent to Thailand to help in the rescue of a group of boys trapped in a cave was a "PR stunt". Mr Unsworth added that Mr Musk could "stick his submarine where it hurts".

Mr Musk responded by calling Mr Unsworth a "pedo guy" in a tweet and a "child rapist" in an e-mail to a BuzzFeed reporter.