After a record-breaking surge in Japanese blue-chip stocks amid all-time high corporate profits, the question is how long can the momentum last.

The Nikkei 225 stock average finally dipped Wednesday, after a 16-day winning streak that took it to the highest level since July 1996. The run-up led into the reporting season for the July-September quarter, which began in earnest this week.

Expectations have been high after the yen traded at an average of 111 per dollar during the three months that ended on Sept. 30, compared with 102.4 for the same period a year earlier. Companies have been delivering so far, with global powerhouses including Canon Inc. and Fanuc Corp. beating analyst estimates and raising their full-year outlooks.