* Nikkei posts longest winning streak in 26 years * Shinsei rises on report it plans to bid for Citi's Japan retail banking business By Ayai Tomisawa TOKYO, Aug 22 (Reuters) - Japan's Nikkei share average rose for the 10th consecutive session on Friday morning thanks to a record close on Wall Street after upbeat U.S. economic data.

Shinsei Bank outperformed the market, rising 2.3 percent after the Nikkei business daily said the bank is planning to bid for Citigroup's Japanese retail banking operations, hoping to take over the wealthy clientele the U.S. bank has built up over decades.

Overall, trading was subdued as investors were focused on Federal Reserve Chair Janet Yellen's speech on Friday at the annual gathering of central bankers in Jackson Hole, Wyoming.

The Nikkei tacked on 0.2 percent to 15,611.35, moving close to a three-week high of 15,759.66 hit on July 31. It rose for a tenth day, the longest winning streak since 1988.

For the week, the index has gained nearly 2 percent.

U.S. home resales raced to a 10-month high in July and the number of Americans filing new claims for jobless benefits fell last week, signaling strength in the economy.

Traders said investors are reluctant to take on big positions ahead of Yellen's speech, which could offer clues on the timing of the Fed's interest-rate hike.

"Even though there may not be a surprise, most investors including event-driven funds want to hold their positions until Yellen's speech is over, and they may take profits after that," said Norihiro Fujito, a senior investment strategist at Mitsubishi UFJ Morgan Stanley Securities.

Exporters were mixed as the recent weakness in the yen paused. The dollar was last at 103.85 yen, not far from the overnight peak of 103.97.

Toyota Motor Corp fell 0.5 percent, Honda Motor Co edged up 0.1 percent and Sony Corp added 0.7 percent.

The broader Topix was flat at 1,291.66, and the JPX-Nikkei Index 400 rose 0.1 percent to 11,761.23.

(Editing by Shri Navaratnam)