Investor reaction to federal finance minister Jim Flaherty’s announcement of a new tax on income trusts send the S&P/TSX composite index down more than 300 points shortly after the opening of trading Wednesday.

The telecom, income trust and energy trust TSX sub-indices all dropped at least 10% in the early trading.

Among the stocks who had previously announced income trust conversion plans, BCE Inc. was off by more than 13% while Telus Corp. dropped by almost 18%. The two phone companies had announced plans to convert to income trusts, but both firms have put their plans under review.