The Bank of Japan will likely end an era of zero interest rates and raise a key short-term interest rate for the first time in six years at its July 13-14 policy board meeting, sources close to the BOJ said. Unless new risk factors emerge, such as a plunge in Tokyo share prices, BOJ Governor Toshihiko Fukui will likely propose raising the key overnight call rate to 0.25 percent from zero, several sources close to the central bank said. But many in the BOJ believe the central bank should maintain very accommodative monetary conditions even after ending zero interest rates, and the BOJ will probably stress that point when they decide to end the zero rate policy, they added. Similar reports by Kyodo news agency and Yomiuri newspaper, which said on Wednesday that the BOJ plans to ends its zero interest rate next week, have helped underscore market speculation for a July rate increase. Japanese government bonds reversed course and turned lower on Wednesday as the market looked past a series of missile launches by North Korea and focused on a possible BOJ rate rise next week. A growing number of market participants expect a hike next week. A Reuters poll released on Monday showed that 32 of 41 analysts and traders said they expected a July rate increase. Such views were bolstered by upbeat results in the central bank's tankan survey, which showed that firms were more satisfied with business conditions in June than they were in March and expect conditions to improve further by September. The survey also showed big firms expect their capital spending to rise 11.6 percent in the year ending next March, beating the market's consensus forecast for an 8.8 percent gain. BOJ Governor Toshihiko Fukui said after the tankan result on Monday that the course of monetary policy was "completely open". Within the BOJ, more central bankers are beginning to worry that keeping interest rates at zero too long could risk overheating corporate capital spending. Some policy board members have pointed to economic slowdown and inflationary pressure in the United States as possible downside risks and said there was still room to discuss the possibility of a downturn in the information technology sector. But the majority view at the central bank is that such factors will not turn out to be serious. Still, BOJ officials will closely watch U.S. jobs data due out on Friday and its impact on U.S. financial markets, the sources close to the BOJ said. Central bank sources have already said that the BOJ may increase the official discount rate -- at which financial institutions borrow money under the BOJ's Lombard lending facility -- to either 0.35 or 0.5 percent from the current 0.1 percent as early as next week.