* Nikkei down for 4 straight days, has fallen 4.6 pct this week
* Exporters with high foreign ownership underperform
* Apple-related stocks fall
By Ayai Tomisawa
TOKYO, Aug 21 (Reuters) - Japan's Nikkei share average dropped more than 2 percent to six-week lows on Friday morning after Wall Street tumbled as investors unloaded risky assets, hit by concerns that a slowdown in China could affect the global economy.
The Nikkei share average fell 2.2 percent to 19,594.13 in midmorning trade, the lowest level since July 9. The index has fallen for a fourth day, and for the week, shedding 4.6 percent so far.
"Due to uncertainly about where China's economy is going, what Beijing will do (in terms of monetary policy) and how much the impact it will have on the global market, anything related to China worries is sold," said Takuya Takahashi, a strategist at Daiwa Securities.
Stocks related to Apple Inc, such as component suppliers, tumbled after the stock fell 2 percent overnight on a report that said overall smartphone sales in China fell in the second quarter.
Alps Electric Co dropped 6.1 percent, Nitto Denko Corp shed 3.1 percent while TDK Corp declined 2.6 percent.
Thirty-two of the Topix's 33 subsectors were in negative territory, and exporters with relatively high foreign ownership underperformed. Sony Corp at one point dived 5.3 percent and Hoya Corp shed 3.4 percent. Foreigners own 56.6 percent of Sony shares, while they own 60 percent of Hoya shares.
Financial stocks also tumbled, with Mitsubishi UFJ Financial Group falling 3.9 percent and Nomura Holdings falling 3.8 percent.
Concern about the Chinese economy was underscored by a near 8 percent slide in the Shanghai stock index so far this week, and after the Commerce Ministry said on Wednesday that exports could continue falling in coming months.
"Foreigners are unloading risky assets as they fear that they will lose money if they own stocks now," said Norihiro Fujito, senior investment strategist at Mitsubishi UFJ Morgan Stanley Securities.
Fujito said that the Nikkei's downside is seen at the 19,115.20 hit on July 9 for the time being, but if it drops below this level, both retail investors and pension funds may buy.
Traders said that the Bank of Japan's buying may support shares while the market stays weak. The central bank bought 33.7 billion yen worth of exchange-traded funds on both Wednesday and Thursday.
Meantime, the short-selling ratio on Thursday was 39.1 percent, according to the Tokyo Stock Exchange, moving closer to a record high of 39.2 percent hit earlier this year.
The broader Topix dropped 2.3 percent to 1,586.95 and the JPX-Nikkei Index 400 declined 2.2 percent to 14,289.49. (Reporting by Ayai Tomisawa; Editing by Eric Meijer)