Bouygues SA shares fell the most in 17 years after talks failed to sell the company’s mobile-phone unit to Orange SA, dashing hopes for a reduced competition in the French wireless market.

Bougues sank 16 percent to 29.46 euros at 9:10 a.m. in Paris after dropping as much as 18 percent, the biggest intraday loss since 1999. Other carriers that would have benefited from consolidation also dropped, with Numericable-SFR losing 17 percent to 30.10 euros, Iliad declining 15 percent to 191.35 euros and Orange sinking 6.6 percent to 14.39 euros.

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