Asia markets open lower as traders assess Aussie business activity data, U.S. tech earnings

Asia-Pacific markets fell on Wednesday as traders assessed July business activity data from Australia, tech earnings from the U.S. and awaited Japan PMI readings.

The region will also look for any spillover effect on tech and EV stocks after U.S. tech giants Alphabet and Tesla reported their second-quarter earnings, with Tesla falling short of estimates.

Japan's Nikkei 225 dropped 0.58% ahead of the PMI announcement, while the broad-based Topix was down 0.43%.

South Korea's Kospi was 0.7% lower, with the small-cap Kosdaq trading marginally below the flatline.

Heavyweight Samsung Electronics plunged 1.8%, even as Reuters reported that chip giant Nvidia had cleared its chips for use in a processor for the China market.

The South Korean electronics company is still grappling with a strike from its largest workers union, with talks on Tuesday yielding no results, according to the National Samsung Electronics Union, which has about 30,000 members.

Australia's S&P/ASX 200 slipped 0.18%, after the country saw its private sector activity expand at a slower pace in July, with the composite purchasing managers' index dropping to a six-month low of at 50.2 compared to 50.7 in June, according to Juno Bank.

Hong Kong Hang Seng index futures were at 17,474, just marginally higher than the HSI's last close of 17,469.36.

Overnight in the U.S., the S&P 500 dipped 0.16% to close at 5,555.74, a day after it notched its best performance in more than a month.

The Nasdaq Composite inched down 0.06%, while the Dow Jones Industrial Average lost 0.14%.

—CNBC's Alex Harring and Samantha Subin contributed to this report.