Taylor Swift wants her fans to head to the polls this November, and if they do, it could swing midterm elections. At least that’s what UBS economist Paul Donovan said in an Oct. 10 note titled “Why @taylorswift13 matters to markets.”

On Oct. 7, Swift urged her Instagram followers to register to vote at Vote.org. By the evening of Oct. 9, over 328,000 people registered on the site. Registration nearly doubled among those aged 18 to 24 and 25 to 29, who make up a large portion of Swift’s fan demographic.

“I can say that we have not seen this much of a lift in registrations in a single 48-hour period,” Vote.org’s Kamari Guthrie said.

It should be noted that some of the spike in registration could be the result of several states having voter registration deadlines in that period.

Donovan wrote that the influx of newly-registered voters add uncertainty to the election. “Recent electoral surprises in the U.S. and elsewhere were caused by the votes of people who do not normally vote,” Donovan said. “New voters reduce U.S. mid-term election predictability.”

If Swift can get more voters to the polls, economists may have a tougher time modeling political risk. “It will make the predictions of opinion polls less accurate,” Donovan said.

‘A number of tangible policy and investment implications’

And a hazier crystal ball could complicate post-election market expectations.

In a Sept. 4 note, UBS’s investment research team noted that the election has “a number of tangible policy and investment implications” that could determine the future of the current bull market.

Republicans could lose control of the Senate if two of their 51 seats flip to Democrats, though the GOP has far fewer incumbents up for election. Twenty-five Democrats, a number of whom are in red states, are fighting for their seats compared to eight Republicans.

In Tennessee, where Swift will vote, Democrat Phil Bredesen is in a tight Senate race against Republican Marsha Blackburn. A CBS poll conducted Oct. 2 through Oct. 5 had Blackburn up 50% to Bredesen’s 42%.

Swift may be helping the Democratic push for control of Congress by announcing she will be voting for Bredesen along with her incumbent House representative, Democrat Jim Cooper.

President Donald Trump on Oct. 9 had a few words to say about Swift’s push. “Let’s say that I like Taylor’s music about 25% less now,” Trump said. The president, however, did not elaborate on how much he liked Swift to begin with.

Brian Cheung is a reporter at Yahoo Finance. Follow him on Twitter @bcheungz