Asian stocks tumbled after renewed jitters about the global economic outlook sparked a selloff on Wall Street, sending U.S. stocks to their lowest levels for the year.
Global financial markets were facing pressure after data showed a steep fall in U.S. consumer confidence and a sharp downward revision to China's leading indicators index. Doubts over the stability of European banks further soured sentiment.
Japan's Nikkei average finished 1.96 percent lower at a key support level, touching a seven-month low and booking its worst quarterly performance since the last quarter of 2008, after the Lehman Brothers collapse.
Charts painted an increasingly bleak picture as the benchmark also posted its third consecutive monthly fall, its poorest such run since the three months from September to November last year.
The benchmark Nikkei shed 188.03 points to 9,382.64 and lost 15.4 percent for the quarter. The broader Topix slipped 1.3 percent to 841.42.
"The fact that the euro is staying near a nine-year low shows that fears about Europe's financial system, which seemed to have run their course, has reemerged and that's leading investors to avoid risk-taking," said Hiroaki Kuramochi, chief equity marketing officer at Tokai Tokyo Securities.
In Asia trade, the euro inched up slightly after striking an 8 1/2-year low of 107.33 yen on Tuesday, when it slid on concerns about European banks' funding ability.
Chip-equipment makers suffered heavy losses as they responded to economic worries and a sharp fall on the Philadelphia Semiconductor Index. Tokyo Electron lost 3.0 percent to 4,855 yen and chip-test maker Advantest dropped 1.6 percent.
Commodities-related firms were also hammered as prices of metals such as copper and zinc tumbled on weak U.S. economic data, worries over European bank financing and concerns over growth for China combined to dash hopes for a quick recovery.
Mitsui Mining & Smelting declined 4.05 percent to 237 yen while trading houses such as Mitsubishi Corp pared early losses to close 1.95 percent lower at 1,864 yen.
Likewise, Seoul shares pared early losses to finish in the red on renewed jitters about the global economic outlook.
The Korea Composite Stock Price Index (KOSPI) finished down 0.55 percent at 1,698.29 points, posting a 3.5 percent gain in June. The index fell as far as 1,675.4 points in the session.
Key exporters and financials led the decliners.
Samsung Electronics, the world's No.1 memory chip maker, and Hynix Semiconductor, the world's No.2, shed 2.2 percent and 2.15 percent, respectively.
In the banking space, with Hana Financial fell 2.5 percent and Shinhan Financial was down 1.8 percent.
But Hyundai Engineering & Construction bucked the trend. Its shares advanced 2 percent after Korea Exchange Bank (KEB) said late on Tuesday that Hyundai's creditors, which include Korea Finance Corp, KEB, and Woori Bank, would kick off the sale process for South Korea's top builder early next month.
Doosan Heavy Industries outperformed slightly, gaining 0.6 percent, after the Korea Exchange asked the company to clarify talk it had won orders to supply parts for a nuclear power facility in the United Arab Emirates, a project being handled by Korea Electric Power Corp (KEPCO).
Concerns over the global economy and stability of European banks dragged Australian stocks 1 percent lower.
The benchmark S&P/ASX 200 index shed 44.2 points to
end at 4,301.5, a five-week low, but was off an intradday trough of 4,249.5.
New Zealand's benchmark NZX 50 index fell 19 points to end at 2,972.1.
Talk that the Australian government was set to water down a hefty new mining tax did little to help mining stocks after metals prices were slammed overnight.
Global miner BHP Billiton fell 1.18 percent and rival Rio Tinto dropped 2.5 percent. Smaller miners such as Kagara ended 4 percent lower and Centennial Coal fell 2.4 percent.
Among financials, investment bank Macquarie Group took the biggest hit, sliding as much as 4.6 percent to a near one-year low of A$36.31, before ending the session down 2.5 percent.
Hong Kong stocks lost ground on Wednesday, on course for their second successive quarterly decline, as global equities slumped on renewed fears about economic growth. But bargain-hunting emerged after the Hang Seng Index touched an early low of 19,971.27.
The benchmark index stood 0.7 percent lower at 20,101.5 points in afternoon trade.
Foxconn International tumbled 8.0 percent to HK$5.05 after the firm surprised markets with a downgrade of its first-half profit forecast.
Defensive sectors such as utilities and telecoms plays outperformed.
Shares in China lost 1.2 percent to hit a fresh 14-month closing low, and posted their biggest quarterly loss in more than two years.
Investor confidence has been shaken, hurt by tight market liquidity as a major IPO loomed.
The Shanghai Composite Indexfinished the day at 2,398.4 points, after Tuesday's break below 2,500 points, a psychological level that had served as a
floor for the market over the past 14 months.
The index dropped 23 percent for the second quarter.
China's stock market remains one of the world's worst performers this year, down nearly 27 percent despite the country's strong economic growth and solid fundamentals.
Taiwan stocks declined 1.27 percent, led by losses in machinery firms and electronic components makers on concerns over demand for their exports.
Components maker Hon Hai sank 5.79 percent after its Hong Kong unit Foxconn warned of a bigger first-half loss.
Financials came under pressure, with Cathay Financial down 1.9 percent and Fubon losing 2.9 percent.
The TAIEX shed 94.2 points at 7,329.37, extending Tuesday's 1 percent fall. The index ended the quarter 7.5 percent lower, compared to its 3.3 percent drop in the first quarter.
In Southeast Asia, indexes in Singapore and Malaysia traded to the downside.