Former President Donald Trump’s chances of beating Vice President Kamala Harris improved significantly in Michigan last week, according to a bookmaker.

Trump’s chances of winning the presidential election in Michigan rose by 14 percentage points on Friday thanks to online betting platform Polymarket. Michigan is considered one of seven battleground states that could decide the presidency on November 5.

While Polymarket still listed Harris as a 52 percent to 48 percent favorite in Michigan, the Democratic candidate saw her lead over the Republican shrink from a much larger lead of 67 percent to 34 percent just a week earlier, on September 27.

Newsweek contacted via email on Friday for comment on the Trump and Harris campaigns.

Polls show that Michigan will most likely be a close race. Although Harris has been a slight favorite over the past two months, Trump has gained ground in the state in some recent surveys.

A pair of Republican polls late last month showed the former president with a 1 to 2 percent lead over Harris. An average of recent polls compiled by FiveThirtyEight shows the Vice President leading Trump by 1.6 percent as of Friday.

Trump was defeated by President Joe Biden in Michigan in 2020 by 2.8 points. He won the state by fewer than 11,000 votes over former Secretary of State Hillary Clinton in 2016, becoming the first Republican to win Michigan since former President George HW Bush in 1988.

The Wolverine State is one of three so-called “blue wall” swing states considered crucial to Democratic hopes of winning in November. Polls and betting in the other two states, Pennsylvania and Wisconsin, are also tight.

Polymarket, which was funded in part by early Trump backer Peter Thiel, has also given the former president a significant opportunity boost in Pennsylvania in the past week. Trump is a 55 to 46 percent favorite in the Keystone State as of Friday, compared to a nearly even contest a week earlier.

FiveThirtyEight’s polling average in Pennsylvania shows Harris with a very narrow lead of 0.6 points over Trump as of Friday.

In Wisconsin, Harris was a slight favorite in Polymarket betting on Friday, although her 52 percent chance of winning was down from 56 percent the week before. The Badger State polls showed the race neck-and-neck, with Harris another 0.6 points ahead of the FiveThirtyEight average.

Polymarket is one of many online betting platforms offering presidential election odds. Almost all bookmakers indicate that Harris and Trump have approximately equal chances of winning the general election in November.

Although betting on elections was technically illegal in the US for years, a federal appeals court earlier this week sided with gambling platform Kalshi in a lawsuit that effectively legalized the practice.