TOKYO, Dec 7 (Reuters) - Japan’s benchmark Nikkei share average pulled back from a more than 29-1/2-year high on Monday, as investors chose to pocket profits amid some concerns of overheating after five consecutive weeks of gains. The Nikkei index fell 0.4% to 26,645.23 by the midday break, after hitting its highest level since April 1991 of at the open. The broader Topix lost 0.47% to 1,767.55. Nearly two-thirds of the 33 sector sub-indexes on the Tokyo exchange traded lower, with metal products, precision instruments and airlines leading the decline. Tokyo stocks opened higher, tracking positive cues from Wall Street’s Friday session, before reversing course on profit-taking. Major U.S. stock indexes rose to all-time highs last week as downbeat U.S. jobs data raised expectations for a new fiscal relief bill. Back home, Prime Minister Yoshihide Suga said on Friday he would decide on an economic stimulus package early this week, adding that green and digital initiatives would be core to the recovery from the coronavirus pandemic. Local stocks have been prone to profit-booking due to persistent concerns of an overheating market, some market participants said. Among the Topix 30 underperformers, Shin-Etsu Chemical Co Ltd fell 3.43% and Hoya Corp slipped 1.58%. The top percentage losers in the index were Rakuten Inc , Olympus Corp and Sumco Corp, dropping between 4.65% and 5.19%. Among individual gainers, semiconductor stocks tracked their U.S. peers higher, with Advantest climbing 1.47% and Tokyo Electron adding more than 1.3%. Dentsu Group Inc inched up 0.85%, after the Japanese advertising giant said it was expecting a smaller net loss for the year ending in December compared to the prior year. (Reporting by Eimi Yamamitsu; Editing by Subhranshu Sahu)