* Nikkei loses steam but still stand near 14-month peak
* Nissan hits 8-year low after top exec leaves for Nidec
* No reaction to Tokyo Stock Exchange re-organisation plan
By Hideyuki Sano
TOKYO, Dec 25 (Reuters) - Japan's Nikkei share average dipped in holiday-thinned trade on Wednesday, while Nissan hit an eight-year low after a top executive tasked with leading a recovery at the troubled automaker abruptly resigned just weeks into his new job.
The Nikkei share average ticked down 0.20% to 23,782.87 while the broader Topix lost 0.39% to 1,721.42, with 34 shares declining for every 10 gainers.
While the Nikkei was not far from a 14-month high of 24,091 hit last week, its rally on the back of optimism on the global economic outlook and U.S.-China trade negotiations has petered out with many players away for holidays.
The dearth of big macroeconomic events prompted traders to focus on shares that had some news.
Nissan Motor fell 3.1% to a low last seen in September 2011 after Jun Seki, its vice chief operating officer and a former contender for CEO, said he was leaving the firm to become the president of Nidec Corp.
His decision is seen as a potential blow to the automaker's push to turn the corner on a scandal involving ousted former Chairman Carlos Ghosn and slumping sales.
Nidec shares gained 0.3%.
Shimamura tumbled 7.6% after the clothing retailer cut its profit estimates for the year to February by about 25%, citing weak sales.
Sugi Holdings lost 6.5% after the drugstore chain operator's quarterly earnings fell short of strong market expectations.
Japan Post Insurance dropped 1.1% and its parent Japan Post Holdings ticked down 0.7% amid media report that the CEO of Japan Post Holdings and two top executives at Japan Post Insurance will resign this week over the improper sales of insurance policies.
Japan Post Insurance has been marred by the scandal for months and its shares have lost almost 30% of their value so far this year, compared to 19% gains in the Nikkei.
The market has shown limited response so far on a proposed overhaul of the Tokyo Stock Exchange that could set a fairly low minimum market capitalisation requirement for the bourse's planned "prime market".
The proposal suggests a few hundred small cap shares could be excluded from the Topix index, market players said.
"The shares that are likely to be excluded are illiquid in the first place so few investors are trying to sell them now," said Hiroyuki Fukunaga, chief executive of Investrust. (Reporting by Hideyuki Sano, Editing by Himani Sarkar)