Pop-up retailers in Philly are betting the house on the Eagles in the Super Bowl

Sunday's Super Bowl is a make-or-break event for Nick D'Ambrosia.

He's among the dozens of pop-up operators who set up shop in Philadelphia in December to cash in on the Eagles' success and be part of a cottage industry that monster sporting events spawn. Pop-ups are retail's vagabonds, chasing demand wherever it takes them and hoping to strike it rich.

In the Philadelphia region, makeshift shops have sprung up at train stations, gas stations, and strip centers — all heavily trafficked areas — from West Chester and Doylestown to a tent inside 30^th Street Station.

D'Ambrosia, 30, sent employees to scout sites in November after it became clear the Eagles were headed to the playoffs. They picked outposts at gas stations in Doylestown, Royersford, Plymouth Meeting, and Pottstown, and at a West Goshen strip center — all busy corners.

"We put everything on the Eagles," said D'Ambrosia, who had a long line inside his 600-square-foot pop-up on the lower level of the posh Shops at Liberty Place in Center City. "It's a risk."

But the decision to pick Philadelphia wasn't hard. His N&D Sports is based in Hamden, a part of Connecticut that is closer to New York than Boston.

"Where I'm from, we hate the Patriots and the Red Sox," he said.

What about this sports-crazed burg?

"Oh, I love Philly," D'Ambrosia said.  "I love the food, especially the cheesesteaks.

"The level of enthusiasm reminds me of Seattle," where he had a pop-up in 2014, he said. "I'm hoping the sales when we add everything up at the end will be the same, too."

He signed a temporary lease and moved in on Jan. 25 for his pop-up at Liberty Place.

Business has been improving daily  this week, he said Friday. "I've been taking money all day today with at least 15 people waiting in line."

N&D Sports creates the designs for shirts and prints them at local printers. The designs depend on the market, said D'Ambrosia, citing the "Embrace the Underdog" shirt.

"I said in my orders, 'If they win the Super Bowl, these are the shirts, flags, sweatshirts, and hats that we want,'" he said.

It was reported this week that national sports retailers were seeing record sales. Since the Eagles clinched a Super Bowl spot, fans have set records for Fanatics Inc., the nation's largest online sports apparel retailer. The sales were driven a lot by the popularity of Nick Foles items, said Jack Boyle, co-president of its direct-to-consumer business.

Pop-ups are popular for huge sporting events like the Super Bowl because once the event is over, it's time to move on to the next one.

"Sports apparel pop-ups are highly versatile," said Steven H. Gartner, managing director of retail services for CBRE Inc. "They're only selling clothing, so they can be pretty much anywhere. I saw one in the grand hall of 30^th Street Station yesterday."

If the Birds win Sunday night, D'Ambrosia said he'll be on the phone after the game with local printers to start the presses. He has runners on standby to pick them up.

"If they win on Sunday we will be getting championship shirts in by Monday, and the rest on Tuesday," he said. "A huge part of the business is who actually the wins the games. It's a huge gamble. I've seen one too many times where the market dried up."

The last two years, he set up shop in Atlanta and Charlotte, N.C. In both years, the Atlanta Falcons and Carolina Panthers lost the Super Bowl.

"The day after the game, I did not see more than five people," he said. "It was sad, but that's what happens when your team loses. It takes a few days to get over it and people start shopping again."

And should the Birds triumph: "We'll be here another week, maybe two, selling stuff. You can be sure."