Raises the estimate after the indices go into positive territory for the year. NEW YORK, April 4 (Reuters) - Merrill Lynch Chief Investment Strategist Richard Bernstein has raised his expected 12-month return on the Standard & Poor's 500 stock index <.SPX> to 12 percent from 8 percent, citing multiple expansions. "Our target is revised to 1590," Bernstein said in a note dated Tuesday. That would pass the record high of 1552.92 set in March 2000. "We do expect multiple expansions in 2007, but one should remember that multiple expansion often comes from falling "E" (earnings) as well as rising "P" (price). Thus, the interaction between earnings and interest rates might become quite important," he wrote.