The Nikkei index on Monday extended its winning streak to three days as the ruling camp’s victory in Sunday’s election gave reassurance on political stability, with gains boosted by the yen’s drop to a new 24-year low against the U.S. dollar on remarks by the Bank of Japan governor. The 225-issue Nikkei Stock Average ended up 295.11 points, or 1.11 percent, from Friday at 26,812.3. The broader Topix index finished 27.23 points, or 1.44 percent, higher at 1,914.66. On the top-tier Prime Market, gainers were led by mining and pharmaceutical issues.