MILAN, Italy — Safilo Group SpA shares plunged on concern that the eyewear maker could lose some business with LVMH, which is nearing a bid for a minority stake in Italian glasses-maker Marcolin SpA, according to people familiar with the matter.

The world’s largest luxury-goods company may buy 10 percent of Marcolin, said the people, who asked not to be identified because the deliberations are private. The stake sale could value all of Marcolin, owned by buyout firm PAI Partners, at as much as €500 million ($531 million), one of the people said. A deal could be announced as soon as this month, though no final decisions have been made, the people said.

LVMH would get more control over the production process at the company, which currently manufactures its Emilio Pucci line of glasses, and may ultimately make Marcolin a production hub for its other brands, including Céline, the people said. Céline has an agreement to manufacture its glasses with Safilo, which is due to terminate at the end of this year.

Shares of Safilo, which also has other license agreements with LVMH, fell 15 percent to €6.75 in Milan at 5 pm after earlier dropping as much as 21 percent, the biggest decline since 2014.

The LVMH agreement — which would follow the union of Ray-Ban maker Luxottica Group SpA and Essilor International SA announced Monday — could also involve investing in Marcolin’s Italian manufacturing operations, as well as the creation of a new company that could eventually absorb all of LVMH’s eyewear licenses, one of the people said.

‘Negative Development’

Safilo, which last year renewed its deal with Dior to end of 2020, said the company is “always actively managing its license agreements,” according to a spokeswoman. She declined to comment on the Marcolin report. Representatives for LVMH, Marcolin and PAI also declined to comment.

“The potential acquisition of a stake in Marcolin would once again reshuffle the opticals space, following the Essilor-Luxottica merger,” said Zuzanna Pusz, an analyst at Berenberg, in a report to clients. “This is likely a negative development for Safilo, which currently has a licensing agreement with some of LVMH’s brands such as Fendi, Céline and Givenchy.”

PAI bought about 80 percent of Marcolin in 2012 in a deal that valued the company at €282 million. Marcolin makes sunglasses for brands including Tod’s and Diesel.

By Daniele Lepido, Manuel Baigorri, Tommaso Ebhardt, Chiari Remondini, Michael Roschnotti, Sarah Syed, Maria Ermakova and Corinne Gretler; editors: Aaron Kirchfeld, Matthew Boyle and Amy Thomson.