Hong Kong (AFP) - Oil prices fell on Monday as investors braced for details of a US plan to isolate the Iranian economy that President Donald Trump billed as the “most crushing” financial operation ever against Tehran.

Eyes are on Treasury boss Scott Bessent, who said he would give more details in a news conference on the fresh push to pile economic pressure on the Islamic republic, which comes as the unpopular war drags towards the six-month mark.

The United States warned allies and China last week to join Trump’s new campaign, although Vice President JD Vance acknowledged that the plan was a “delicate dance” because Iran will “try to apply economic pressure to us”.

Asked whether the United States would pressure China, Bessent told CNBC that “many conversations are best to have in private”, but he also called on Beijing “to get with the programme”.

Both main crude contracts were down around two percent, with the Brent benchmark sitting at $92 a barrel.

Asian stocks were mostly down, with South Korea’s tech-rich Kospi falling more than three percent after Samsung Electronics said it spent $80 billion to buy back its own shares following weeks of turbulent trading.

The chip giant’s shares, along with those of rival SK hynix, peaked in June on optimism for the artificial intelligence boom, but have since fallen amid investor jitters and a broader tech rout.

- AI’s big week -

Tokyo and Shanghai closed down 0.7 percent and 0.6 percent respectively, echoing losses across Asia that included Taipei, Wellington, Bangkok, Mumbai and Jakarta. Sydney, Singapore, Manila and Kuala Lumpur posted marginal gains.

Hong Kong closed nearly two percent down despite fast-fashion giant Shein announcing its market debut will take place in the Chinese financial hub on September 1.

The long-awaited listing would value the group – known for its vast selection of products at stunningly low prices – at close to $27 billion.

London was flat, while Paris and Frankfurt were down.

In an important week for AI, investors are also looking towards an earnings report from Nvidia, the world’s most valuable company and a bellwether for the sector.

The recurring question for the US chipmaker is whether the AI boom will continue to accelerate as the technology takes over more corners of the broader economy.

“The spending machine is still running, but the bill is getting heavier,” said Stephen Innes of SPI Asset Management.

“Nvidia must now show that the most expensive investment boom in modern market history can still pay its bills.”

Chinese tech giant Alibaba is keeping focus on the sector after announcing on Sunday that it plans to issue $10.2 billion in new shares in Hong Kong to fund its global AI ambitions.

The firm, known for its open-source “Qwen” AI models, has been ploughing tens of billions of dollars into the technology, with shareholders eager to see how it will monetise the huge investments.

Traders will also be watching this week’s annual gathering of central bankers, economists and finance chiefs in Jackson Hole in the United States, hoping for some clarification on US monetary policy.

The meeting comes after the Treasury bought its own bonds last week in an effort to push down borrowing costs after the 30-year yield surged to levels last seen in 2007, just before the global financial crisis.

Yields have risen on inflation fears and as the United States reported that its federal debt had topped $40 trillion.

- Key figures at around 0815 GMT -

Tokyo - Nikkei 225: DOWN 0.7 percent at 65,528.09 (close)

Hong Kong - Hang Seng Index: DOWN 1.9 percent at 25,517.33 (close)

Shanghai - Composite: DOWN 0.6 percent at 3,882.01 (close)

London - FTSE 100: FLAT at 10,812.98

Dollar/yen: UP at 159.11 yen from 159.03 yen on Friday

Euro/dollar: DOWN at $1.1671 from $1.1679

Pound/dollar: DOWN at $1.3642 from $1.3647

Euro/pound: DOWN at 85.55 pence from 85.58 pence

West Texas Intermediate: DOWN 2.2 percent at $85.11 per barrel

Brent North Sea Crude: DOWN 1.8 percent at $92.69 per barrel