Donald Trump’s political fortunes are rising thanks to a surprise 11th-hour one-two punch — national polls are tightening with Hillary Clinton’s missteps while a key Wall Street indicator that has correctly predicted past elections is lining up in the billionaire’s favor.

The S&P 500 Index is down 3.6 percent since Aug. 8 — a trend that could signify a Trump victory next week, according to an analysis cited in a Bloomberg report. That’s because when there’s a gain in the index during the three months prior to the vote, the incumbent party — in this case, Democrats — have won 86 percent of the time since 1928. The pattern has rung true 100 percent of the time since 1984.

“It’s very good news for Trump,” said Republican strategist Dave Carney. “This is the first administration since (President Herbert) Hoover not to have one year of 3 percent growth or more. They can brag all they want, but nobody in the middle class believes they’re better off today than they were eight years ago and that’s really Trump’s strongest message, that it’s time for a change.”

Other indicators also suggest Wall Street is bracing for a Trump presidency. The value of the peso in Mexico — where Trump wants to build a wall, billing that country for construction costs — has fallen 2.1 percent against the U.S. dollar, while the Vix index, known as Wall Street’s “fear gauge,” approached highs rivaling those following the UK’s successful Brexit vote, according to the Financial Times.

“A lot of these indices and signs point to a Trump victory,” said GOP strategist Ford O’Connell. “I think it’s a very different signal than what the mainstream media is sending. Everywhere you look, generally speaking, everyone in the media is pointing to Trump losing. … For a while, Wall Street was certain that Hillary Clinton was going to win. Now … they’re kind of holding the phones.”

Meanwhile, Clinton has lost her momentum and Trump is surging in national polls, on news such as soaring Obamacare premiums and the FBI’s discovery of thousands of new Clinton-linked emails on disgraced former U.S. Rep Anthony Weiner’s laptop.

An ABC News/Washington Post tracking poll that had Clinton leading by 12 points just nine days earlier now shows Trump ahead by 1 point, 46-45 percent.

Trump was also on top by 4 points in an L.A. Times/USC tracking poll yesterday. Other national polls showed the race much closer, including an Investor’s Business Daily survey with Clinton up 1 and a Rasmussen poll that has them tied.

Still, Clinton holds a big lead on the all-important electoral map with key battleground states, such as New Mexico, Pennsylvania and Virginia, leaning Democratic.

Both rivals upped their attacks on each other yesterday, just a week before Election Day.

Trump, campaigning with running mate Mike Pence in Valley Forge, Pa., blasted Clinton’s links to the Affordable Care Act.

“If we don’t repeal and replace Obamacare, we will destroy American health care forever,” Trump said.

Clinton had spent Monday suggesting Trump has ties to the Russian government, but both CNN and The New York Times reported FBI investigations have so far found no link.

So Clinton reopened a front against Trump on his treatment of women, running minute-long TV ads in battleground states using the former reality TV star’s words against him. Former Miss Universe Alicia Machado, who accused Trump of fat-shaming in the mid-1990s, also introduced Clinton at a rally in Florida.

“Can we just stop for a minute and reflect on the absurdity of Donald Trump finding fault with Miss Universe?” Clinton said. “You’ve got to ask, why does he do these things? Who does this? I will tell you who — a bully.”