(Reuters) - Shares of Trump Media & Technology Group ( DJT ) fell 17% in premarket trading on Wednesday after Democratic candidate Kamala Harris extended her lead over Republican rival Donald Trump in betting odds following a combative presidential debate.

Harris put Trump on the defensive with a stream of attacks on his fitness for office, his support of abortion restrictions and his myriad legal woes, prompting a visibly angry Trump to deliver a series of falsehood-filled retorts.

After the debate, pricing for a Trump victory slipped by 6 cents to 47 cents on online betting site PredictIt, while Harris's odds climbed to 57 cents from 53 cents.

Harris's candidacy also received a boost after pop megastar Taylor Swift said she will vote for the Democratic candidate to her 280 million followers in a post on Instagram.

"The U.S. Presidential debate achieved its goal by providing a decisive edge to one of the candidates in what has been an exceptionally close race," said Charu Chanana, global market strategist at Saxo.

"The debate (was) .. further energized by Taylor Swift's endorsement, which could boost support from women and younger voters.

Trump is the biggest shareholder in Trump Media & Technology Group ( DJT ) , the parent of Truth Social app, which is popular among retail traders and is often sensitive to the former president's chances of winning the 2024 U.S. election.

Trump Media's ( DJT ) valuation is equivalent to more than 900 times the money-losing company's revenue in 2023 of $4.1 million, far exceeding the worth of much larger companies with more revenue.

For instance, Meta Platforms, which earned $131.9 billion from goods and services in 2023, has a price-to-revenue valuation of 9.6, according to LSEG data.

Since its listing through a reverse merger with a blank check firm in March, TMTG's market value jumped as much as $9.2 billion in late May before dropping to $3.7 billion up to Tuesday's close.

About 320,000 shares Trump Media ( DJT ) shares changed hands in early premarket trading, making it one of the most actively traded Nasdaq stocks.

(Reporting by Medha Singh in Bengaluru; Editing by Saumyadeb Chakrabarty)