Nov 5 (Reuters) - US labor productivity accelerated in the third quarter, posting the fastest growth in a year—a reflection of companies' efforts to improve efficiency and ease rising costs. Data from the US Bureau of Labor Statistics on Thursday showed that nonfarm business output per hour rose at an annualized rate of 3.6%, up from an upwardly revised 2.1% in the previous quarter. Unit labor costs fell 0.7%, marking the first decline since the second quarter of 2025. Labor costs are among companies' largest expenses, and firms are ramping up investment in new technologies and equipment to boost employee efficiency. Productivity gains help companies limit the extent of price increases. The latest data may indicate that, amid sharply rising input costs, the current capital expenditure boom is gradually translating into efficiency gains. Companies have invested heavily in artificial intelligence, software and equipment, and these investments are expected to enable firms to achieve higher output with unchanged labor input. Another US government report on Thursday showed that first-time claims for unemployment benefits fell last week to a level comparable to the lowest since 1969, underscoring the stability of the labor market.