"The market is currently assuming Telstra maintains a dominant market share position in fixed-line broadband and mobile into perpetuity, but that could prove optimistic," said Citigroup analyst Tim Smeallie, who said a break-up could push the share price down to A$3.70. Telstra, under Chief Executive Sol Trujillo, has taken a combative stance on regulation and is suing the government in two separate cases, one over funding to arch rival Optus. Macquarie Equities analyst Andrew Levy said a break-up would be a negative for Telstra, but not devastating, with the biggest impact likely to be on the firm's five-year overhaul plan.