Since 1986, Mori Building Co., Ltd. (Head office: Minato-ku, Tokyo; President and CEO: Minoru Mori) has periodically carried out surveys of demand and supply trends for large office buildings with total office floor space exceeding 10,000 m2 (in this survey, these structures will be referred to as "large-scale office buildings") throughout Tokyo's 23 wards. We have also analyzed the results of the surveys from various perspectives and forecast future office market trends. This summary report gives survey results as of the end of December 2005.