President Biden's decision on Sunday to drop out of the presidential race and Vice President Harris gaining the support to become the Democratic Party's presumptive nominee hasn't caused a dramatic shift in betting markets' views of the matchup with Republican nominee former President Trump.

Biden's decision on July 21 to withdraw from the race came after intense pressure from Democrat politicians who were concerned about his waning support amid concerns over his health and mental acuity in the wake of his poor debate performance against Trump on June 27.

Biden's odds of winning a second term plunged from about 45% on PredictIt on the eve of the debate to 15% on Saturday, the day prior to his decision to withdraw. Bettors on Polymarket cut his odds from about 34% to 7% in that time frame.

As of Wednesday evening, traders on Polymarket gave Trump a 63% chance of winning while Vice President Harris had 32%, with Trump's odds mostly unchanged since Sunday's development. On PredictIt, Trump's odds have dipped slightly from 60% on Sunday to 57% as of Wednesday, and Harris' odds rose from 40% to 45% in that time.

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Bettors have flocked to prediction market sites in the days since Biden's announcement amid the volatility in the presidential race.

"There has been close to record trading on the PredictIt site over the last few days, and that has continued with Biden's announcement on Sunday," PredictIt Public Relations Director Lindsey Singer told FOX Business on Wednesday. 

Singer noted that the addition of a market for the new Democrat vice presidential nominee on the PredictIt platform has also proven "very popular" with traders since Biden's withdrawal and Harris becoming the party's presumptive nominee.

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Sen. Mark Kelly, D-Ariz., leads the vice presidential market as of Wednesday with a 35% chance in the eyes of bettors. That amounts to a modest lead over second-place contender Pennsylvania Gov. Josh Shapiro, who has a 31% chance.

Those two have a notable advantage over a pair of Democrat governors who have been discussed as potential vice presidential picks. North Carolina Gov. Roy Cooper had a 15% chance, while Kentucky Gov. Andy Beshear had a 12% chance as of Wednesday.

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Other possible vice presidential nominees for PredictIt's bettors include Transportation Secretary Pete Buttigieg at 9% and Minnesota Gov. Tim Walz at 8%.

Buttigieg appeared on FOX Business Network's "Cavuto: Coast to Coast" on Wednesday, and host Neil Cavuto asked Buttigieg, "[C]ould the Department of Transportation afford to lose you if you joined a Kamala Harris ticket?"

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"I admire the creativity of how you tried to get me into this, but I just can't talk about campaigns and elections here," Buttigieg replied. "What I will say is, you know, as a government matter, I'm proud of the work of the department, and I'm proud to work with the leadership of the president and vice president."