Alumina's proposed share buyback could be between A$250 million and A$350 million, Macquarie says. Says Alumina FY result solid and in line with forecasts. "The higher dividend is good news, the potential for an offmarket buyback is even better, and for us, the value is certainly there," Macquarie says. Maintains Outperform rating and A$7 price target. Alumina up 2.0% to A$6.96 in early trade.