Business sentiment among large manufacturers worsened for the third straight quarter amid concerns over increased trade friction and the impact of natural disasters, according to the Bank of Japan's tankan survey.

The key index measuring confidence among companies such as automobile and electronics makers, released Monday, stood at plus 19 in the September survey, down two points from June. The result was weaker than the average market forecast of plus 22 in a Kyodo News poll.

This is the longest streak of negative results for the tankan since a six-quarter run between December 2007 and March 2009, lending weight to the view that growth in the world's third-largest economy may have slowed in the third quarter.