Vinci SA, Europe’s largest construction firm, is weighing an offer for a controlling stake in Groupe ADP if the French government decides to privatize the airport operator, people familiar with the matter said. Vinci, which holds 8 percent of ADP, is working with financial advisers as it explores a bid for the business, the people said, asking not to be identified as the information is private. ADP shares have risen 25 percent since Emmanuel Macron topped the first round of voting in the presidential election in April, giving the Paris-based company a market value of about 14.3 billion euros ($15.9 billion). Vinci is keen to take full control of ADP, one of the people said. France may also decide to reduce its 50.63 percent stake gradually through a capital markets deal, rather than selling the entire holding to a buyer, the people said. An offer for ADP, which operates the Paris Charles de Gaulle and Orly airports, would require the French government to pass a privatization law, which means a deal may not happen until next year, one of the people said. No final agreements have been reached and discussions may not lead to a deal, the people said. Other companies may also be interested in bidding for ADP, they said. Representatives for Vinci, ADP and France’s finance ministry declined to comment. Agence des Participations de l’Etat, the country’s shareholding agency that holds the ADP shares, didn’t return a message. Divestment Program Macron is considering embarking on a divestment program to raise funds that could be put towards a program to boost innovation. The nation is unusual among big western European countries in that it has a broad portfolio of stakes in publicly traded companies, in addition to closely held businesses such as military shipbuilder DCNS and lottery operator Francaise des Jeux. Vinci raised its holding to 8 percent stake in 2013 and won a seat on the board. Dutch airport operator Royal Schiphol Group NV also owns 8 percent, according to data compiled by Bloomberg. Vinci’s airports division owns stakes in 35 airports worldwide including in Portugal, Japan and Cambodia in addition to 13 in France, according to the company’s website. Vinci was part of a consortium that last year acquired a controlling 60 percent stake in the Lyon airport concession as part of a privatization drive under former President Francois Hollande. ADP shares rose 3 percent to close at 144.80 euros in Paris trading on Wednesday, the biggest gain in almost a month. Vinci fell 0.5 percent to 79.50 euros.