Telefonos de Mexico had taken a beating even before the bolsa collapsed. Now, Telmex' U.S. shares trade around 27, from 65 last August. For SBC, the U.S. phone company with 10% of Telmex' controlling shares, that represents a $2.6 billion paper loss. Bell Atlantic has taken a hit, too: It owns 42% of cellular operator IUSACELL, whose stock is down 35%. But their outlook is upbeat. Fewer than 9% of Mexicans have access to a phone line, leaving room for growth. AT&T, GTE, MCI, and Motorola all have partnerships with Mexican companies to bid for long-distance concessions.