The closing of the flagship location of the former Vetri restaurant Amis Trattoria has been moved up to Sunday from its original Aug. 30 date.

Owner Urban Outfitters, which announced the closing in May, did not disclose the reason for the hastened shutdown after 9½ years, but it’s likely due to staffing and slower summertime business.

Founder Marc Vetri, who with business partner Jeff Benjamin sold Amis and several other restaurants to the South Philadelphia-based retail giant more than three years ago, described Amis as “a very special place” and “a neighborhood gem.”

Amis, conceived by Vetri and chef Brad Spence, opened in early 2010 at 13th and Waverly Streets, around the corner from the posh Vetri Cucina on Spruce Street.

“I remember working with Brad at Vetri, and him telling me he wanted to open a simple neighborhood restaurant,” Vetri said Friday. “We went to Rome, and we knew what we had to do. We tested cacio e pepe a thousand times in six months at Vetri.... We’ll always have cacio e pepe.”

The name, pronounced “ah-MEES," is Roman slang for “friends.” Though the room’s hard surfaces and rock-and-roll soundtrack created a din, the food — “mosaic of simple but vivid flavors,” in the words of Inquirer food critic Craig LaBan — drew cognoscenti.

It also drew the attention of Vetri’s father, Sal, who, with former Inquirer food columnist Rick Nichols, joyfully set up camp in the kitchen to cook meals for the staff — “getting in the way of the real chefs each Friday,” in the words of Nichols: “Meat loaf was a favorite, and chicken cacciatore, and pasta Bolognese, always seasoned with Sal’s secret sauce: Butter. And a dash of red vermouth.”

As a result of Sal Vetri’s tutelage, Nichols said, “I have emerged as Narberth’s king of eggplant caponata.”

"It was amazing working with so many great people over the years,” said Spence, who left Urban’s employ in May, shortly before the closing was announced. “Hopefully, I get the chance to work with them again one day.”

Spence, also an artist, is getting ready for his first gallery show.

Other Amis locations, in Devon and Westport, Conn., are unaffected.