Shares flat in Asia before Iran sanctions news

Share markets are flat in Asia and oil prices have eased as investors await details of threatened US sanctions on Iran due later in the session, while the Canadian dollar has dipped as a trade war looms with its southern neighbour.

The entire tech sector is holding its breath for Nvidia's results on Wednesday; investors are aware how hard it will be for the chip maker to meet stratospheric expectations.

Analysts are generally looking for quarterly revenue to almost double to around $US92 billion ($A128 billion), with full-year earnings guidance seen in a range of $US103 billion ($A144 billion) to $US105 billion ($A146 billion).

Market participants will also be hoping for some clarity on the outlook for US interest rates when Federal Reserve Chairman Kevin Warsh speaks in Jackson Hole, Wyoming, on Friday, though his well-known aversion to forward guidance could lead to disappointment.

"There are several reasons to expect to be underwhelmed," said Bruce Kasman, chief economist at JPMorgan, noting that past chairs have not wanted to front-run Fed decisions at the event.

"Warsh will rather likely focus on aspects of his 'regime change' agenda," Kasman added.

"As the Fed has already been moving toward shrinking the balance sheet, and the committee gave the balance sheet some attention in the July minutes, that might be the most likely topic for him to expound upon."

Markets imply around a 40 per cent chance that the Fed will raise interest rates when it meets on September 16 and are fully priced for a move by December.

The odds could change depending on what US inflation figures show this week, with median forecasts for core inflation expected to hold at 3.3 per cent in July.

Warsh is sure to face questions about Treasury Secretary Scott Bessent's surprise announcement last week of at least a doubling in bond buybacks, aimed at restraining a rise in yields that was tightening financial conditions in the economy.

His efforts have had little success so far, with 30-year yields back up at 5.2760 per cent, not far from the recent 19-year peak of 5.3371 per cent.

Higher yields make debt more attractive compared to equities while lifting the discount applied to future earnings, highlighting the stretched nature of some valuations.

Bessent is due to hold a news conference later on Monday to outline sanctions on Iran, which has shown no sign of relinquishing its control over the vital Strait of Hormuz.

Brent slipped 1.0 per cent to $US93.43 ($A130.33) ahead of the announcement, though that followed gains of 6.6 per cent last week. US crude eased 1.1 per cent to $US86.14 ($A120.16) a barrel.