MT Newswires -ShutterstockSingapore shares plunged further on Wednesday, despite mediators continuing their efforts to ramp up a peace deal between the US and Iran. The Straits Times Index (STI), a key benchmark for the Singapore Exchange, ranged between 5,568.48 and 5,614.84 throughout the day. It ended the session at 5,581.37, down 30.88 points or 0.6% compared to Tuesday's close. In economic news, Singapore's total retail sales rose 4% year-over-year to SG$4.2 billion in June, following a 2.9% increase in the prior month, according to data from the Statistics Department. Meanwhile, United Overseas Bank (SGX:U11) signed a share purchase agreement with Allianz Global Investors for the sale of all its shares in UOB Asset Management for SG$555 million.