* JDI nosedives after it says to cut jobs, downsize mobile ops
* Tokyo Electron, Advantest tumble
* Banks weak on prospects for U.S. rate cut
* Eyes on geopolitical risk amid extradition protests in Hong Kong
By Ayai Tomisawa
TOKYO, June 13 (Reuters) - Japan's Nikkei fell on Thursday morning, with chip-related shares battered after their U.S. counterparts tumbled while concerns over U.S.-China trade frictions kept activity in check.
The Nikkei share average dropped 0.8% to 20,958.25 at the midday break.
Chip-related stocks lost ground, with Tokyo Electron and Advantest Corp down more than 4%, after the Philadelphia Semiconductor index dropped 2.3%, while Micron Technology Inc and Applied Materials Inc both slumped more than 5%.
"Japanese tech shares took a hit as global investors are likely unloading shares in the overall tech sector," said Yutaka Miura, a senior technical analyst at Mizuho Securities.
Concerns over trade continued to weigh on sentiment, after U.S. President Donald Trump on Tuesday said he was holding up a deal with China and had no interest in moving ahead unless Beijing agrees to four or five major points.
Analysts said trading volume would likely be thin as investors await more cues for trade at the G20 summit this month, while they are also on the sidelines before the June settlement of Japanese stock futures and options on Friday.
Investors were keeping a close eye on violent protests in Hong Kong over an extradition bill that would allow people to be sent to mainland China for trial.
"A geopolitical risk has emerged amid Hong Kong extradition protests," said Masayuki Doshida, a senior market analyst at Rakuten Securities.
"Investors might not have positioned themselves based on this yet, but depending on developments, it could be a reason to dent the market in the future."
Hong Kong authorities were shutting government offices in the city's financial district for the rest of the week after a day of violence over the bill.
Financial stocks, which benefit from higher rates, languished on growing views the Federal Reserve will cut interest rates. Mitsubishi UFJ Financial Group fell 2% and Sumitomo Mitsui Financial Group dropped 1.3%.
Japan Display Inc nosedived 12% after the struggling smartphone screen maker said it would downsize its mobile business and cut 1,200 jobs.
The broader Topix fell 1.2% to 1,536.10, with all of its 33 subsectors in the red. (Editing by Jacqueline Wong)