* Nikkei down for second day, U.S. data awaited
* Trade thin amid Japan summer holidays
* Fast Retailing gains on Goldman Sachs upgrade
* Asahi up on purchase of NZ Independent Liquor
TOKYO, Aug 18 (Reuters) - Japan's Nikkei stock average fell for a second straight day on Thursday, hurt by worries about a persistently strong yen and the outlook for global growth, with many investors also reluctant to trade ahead of U.S. economic data
U.S. data due on Thursday that will help investors gauge the strength of one of Japan's main export targets. Reports include consumer prices, existing home sales and manufacturing data for the mid-Atlantic region.
"The biggest problem for investors right now is the strong yen," said Koichi Ogawa, chief portfolio manager at Daiwa SB Investments.
A strong currency undermines the value of Japanese exporters' overseas profits, and also makes Japanese shares less attractive to investors holding other currencies.
The benchmark Nikkei fell 0.6 percent to 9,000.73, slipping further from one-week intraday high of 9,150.31 hit on Tuesday, while the broader Topix index fell 0.6 percent to 771.53.
Trade however has been thin this week as many domestic market participants are on summer holidays and as foreigners wait for the U.S. data.
"Without the active participation of overseas institutional investors, it's difficult for the market to rise," Ogawa said.
Fast Retailing , operator of the Uniqlo casual clothing chain, rose 3.5 percent to 14,880 yen after Goldman Sachs raised its rating to "buy" from "neutral", citing growing demand in Asia.
Beer maker Asahi Group Holdings gained 1.8 percent to 1,617 yen after it said it will buy all shares in New Zealand's Independent Liquor Ltd from its two investment-fund owners for 98 billion yen ($1.3 billion) next month.
Japanese trade data released before the market open showed exports fell 3.3 percent in July from a year earlier, logging a bigger drop than the previous month as a strong yen and a slowdown in overseas demand harm Japan's export recovery. ($1 = 76.565 Japanese Yen) (Reporting by Hideyuki Sano and Lisa Twaronite; Editing by Edwina Gibbs)