Book-to-bill ratio
The book-to-bill ratio, also known as the BB ratio or BO/BI ratio, is the ratio of orders received to the amount billed for a specific period, usually one month or one quarter. It is widely used in the technology sector and especially in the semiconductor industry, where the semiconductor manufacturing equipment (SME) book-to-bill ratio is considered an important leading indicator of demand trends. A book-to-bill ratio above one means that more orders were received than filled, indicating strong demand, while a ratio below one indicates weak demand. Reports SEMI Semiconductor Equipment and Materials International (SEMI) publishes a monthly book-to-bill report for SME manufacturers headquartered in North America. The report is based on confidential bookings and billings data for 22 different equipment categories, broken down into seven regions: "North America", "Japan", "Europe", "Taiwan", "Korea", "China", and "Rest of World". SEAJ The Semiconductor Equipment Association of Japan (SEAJ) publishes monthly book-to-bill reports for SME, LCD, and related equipment manufacturers headquartered in Japan. Like the SEMI reports, the SEAJ reports are based on three-month moving averages. Detailed reports are available to SEAJ members and manufacturers who participate in the SEAJ data collection program. As of 2005, Japanese and North American SME manufacturers each