A megacap tsunami coming your way

July 25 (Reuters) - A look at the day ahead in Asian markets by Alden Bentley in New York

Brace for fallout from a megacap-led wipe out. A rethink of the earnings picture for hyped up AI and Magnificent seven stocks turned a run on Alphabet and Tesla into a Wall Street rout.

Combine that with concerns about Chinese and global growth that heaped pressure on commodity linked currencies and you have the makings for the risk-off mood in China's markets, and Japan's, to continue.

However the November U.S. election plays out there are risks for Chinese companies. Vice President Kamala Harris has emerged as the Democratic presidential candidate after President Joe Biden, 81, ended his re-election bid on Sunday. It is not clear how what kind of China policy she will favor but she and rival Republican Donald Trump are expected to take tough stands on tariffs and Taiwan, as Biden has.

The Democratic National Committee's rules committee agreed on Wednesday on a plan to formally nominate Harris as soon as Aug. 1 -- before the party's Aug. 19-22 convention in Chicago -- with Harris picking a running mate by Aug. 7

The S&P 500 and Nasdaq skidded to multi-week lows on Wednesday after Tesla and Alphabet disappointed with lackluster earnings and their shares tumbling 12% and 5%, respectively.

The tech-heavy Nasdaq ended 3.6% lower and the S&P 500 fell 2.3%. Other megacaps, Apple (AAPL.O), Microsoft (MSFT.O), Amazon.com (AMZN.O), Meta Platforms (META.O) and Nvidia (NVDA.O), took it on the chin, as did small caps, which enjoyed a brief moment in the sun in recent weeks.

The dollar fell to its lowest in more than two months against the yen as short-yen carry trades were unwound ahead of next week's Bank of Japan meeting. That coincides with the July 30-31 FOMC meeting. While the Fed is unlikely to pull the trigger on easing this month, a scenario in which yield differentials soon narrow from both sides is being built in.

Until then, the main macro headlines to trade on come on Thursday, when the first estimate of second quarter U.S. GDP comes out, and Friday with the release of the Personal Consumption Expenditure Price Index which the Fed relies on to gauge inflation.

The Australian and New Zealand dollars were noted losers because of the economic tie to raw materials. Oil prices, while up on Wednesday, are near their lowest in a month and a half and industrial metals like iron ore and copper hit 3-1/2-month lows on a gloomy outlook for Chinese demand.

Here are key developments that could provide more direction to markets on Thursday:

- South Korea GDP (Q2 advance)

- Japan service PPI (June)

- U.S. GDP (Q2, advance)