This report is from today's CNBC Daily Open, our international markets newsletter. CNBC Daily Open brings investors up to speed on everything they need to know, no matter where they are. Like what you see? You can subscribe here.

What you need to know today

Nvidia sinks
Nvidia shares plummeted 9.5% Tuesday. Nvidia's slide continued in extended training, falling 2% after it was reported the company received subpoenas as part of an antitrust investigation. Perhaps aware of the risks, more than half of Tiger 21's members – a club of ultra-high-net-worth investors – don't invest in Nvidia.

Ugly markets
Dragged down by Nvidia's plunge and weak economic data, U.S. stocks had their worst day since Aug. 5's sell-off. Taking a lead from the U.S., Asia-Pacific markets plunged Wednesday. Japan's Nikkei 225 sank more than 4%, Korea's Kospi index fell around 3% and the Taiwan Weighted Index dropped 4.5%.

Weak links in Nvidia's supply chain
The abovementioned Asian markets slid so dramatically because they comprised Asian chipmakers most connected to Nvidia's supply chain. SK Hynix, which sank 8%, and Samsung Electronics, which fell 3.3%, produce memory chips for Nvidia. TSMC, which manufactures Nvidia's graphic processing units, declined 5.4%.

Low heat
U.S. crude oil futures fell more than 4% Tuesday and continued dropping around 0.6% during Asian trading hours. U.S. West Texas Intermediate prices are now trading at $69.88 a barrel, more than erasing its gains for 2024. That's because of a possible restart of Libya's oil production, an increase in supply by OPEC+, and weak demand by China's economy.

[PRO] Powering AI
The energy sector is a natural beneficiary of the artificial intelligence frenzy. AI data centers suck up lots of power, which means energy companies are a good adjacent play to technology stocks – and RBC Capital Markets thinks this oil and gas stock has a potential upside of 25%.

The bottom line

Some investing advice from an unlikely source: the recently reunited British band Oasis. In one of their songs, they croon, "Hold on/ Don't be scared/ You'll never change what's been and gone."

Investors should keep that in mind as they absorb the market's Tuesday move. The S&P 500 slipped 2.12%, the Dow Jones Industrial Average dropped 1.51% and the Nasdaq Composite lost 3.26% (ouch).

A confluence of factors was probably behind markets' weakness on Tuesday.

First, U.S. manufacturing activity remained in contraction territory for August. That resurrected concerns the U.S. economy isn't as strong as it looks.

Next, Nvidia sank almost 10%. Other chipmakers, in both the U.S. and Asia, were hit by the shockwave as well. Intel lost 8.8%, SK Hynix sank more than 7% and Tokyo Electron declined 8.7%. And in extended trading, Nvidia slipped around 2% on reports the U.S. Department of Justice is starting to investigate the chipmaker for antitrust reasons.

Last, some of that grim mood could have just been expectations.

Historically speaking, September has been the worst month for the S&P. The index's lost an average of 2.3% over the past 10 Septembers, according to FactSet data.

That's all to say: Yes, there are real reasons to feel concerned for the month. Fundstrat co-founder Tom Lee warned investors to be cautious for the next eight weeks, and thinks stocks could pull back by 7% to 10%.

But it's also important not to react impulsively.

Even though the ISM reading shows manufacturing activity declined, it's more than 42.5%, which generally signals expansion across the broader economy, noted Timothy Fiore, chair of the ISM Manufacturing Business Survey Committee.

And Nvidia's still up 118% for the year, even after its $300 billion wipeout in capitalization on Tuesday.

As another Oasis song exhorts, when it comes to investing for the long term, we should remember "The Importance of Being Idle." Don't let panic take over.

– CNBC's Jeff Cox, Alex Harring and Fred Imbert contributed to this report.