Investors ranging from institutional accounts to retail clients sunk about $1 billion into tech stocks during the past week, driving inflows to the highest annualized pace in 15 years, Bank of America/Merrill Lynch (BAC) - Get Report noted today.

BofA analysts said that 30% gains in Facebook (FB) - Get Report and Apple (AAPL) - Get Report have continued to help prolong the rally, but 84% of technology stocks have seen positive returns this year.

"The longer it takes the economy and yields to pick up, the greater risk of tech mania," the analysts wrote, adding that the Nasdaq Internet index is on pace for a 75% gain for the year.

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