SHARES in GPT Group, Australia's fourth-largest real-estate investment trust by market value, dropped 15 percent in Sydney trading yesterday, the most in more than two decades, after cutting its full-year operating profit and dividend estimates.

The shares fell 36 Australian cents to A$2.10 at the close of trading on the Australian Stock Exchange, the lowest since 1996 and the biggest drop since the October 1987 crash.

GPT shares have almost halved since the start of the year, Bloomberg News reported.

The firm lowered its operating profit estimate to A$464 million (US$447 million) from A$633 million, citing worsening conditions in global financial and property markets.

GPT cut its dividend forecast to 20 Australian cents a share and lowered earnings per share guidance to 21.20 cents for the year to December 31, 2008, in a statement yesterday to the Australian Stock Exchange.