US stock indexes climbed on Monday after artificial intelligence developer Anthropic filed for an initial public offering, and investors prepared for a key week of earnings from major tech companies.

The S&P 500 rose 0.8%, bringing the index to within 1.6% of its record set earlier this month. The Dow Jones Industrial Average gained 154 points, or 0.3%, while the Nasdaq composite advanced 1.1%.

Australian markets were set for a small lift at the open, with futures pointing to a rise of 11 points, or 0.1%. The ASX had gained 0.2% in Monday trade. The Australian dollar was trading at US70.25¢.

Anthropic PBC filed paperwork with the US Securities and Exchange Commission as it prepares to list in the United States. The company behind the Claude chatbot is expected to trade on the Nasdaq Global Select Market under the symbol ANT, following a confidential filing in June.

Investors and bankers tracking demand say recent conversations have pushed some valuation estimates down to roughly US$1.4 trillion to US$1.5 trillion (about A$2.0 trillion to A$2.1 trillion), while other participants believe a valuation closer to US$1.75 trillion remains possible.

Chipmaker Nvidia led gains among AI-exposed names, climbing 2.5% and regaining ground after three losing weeks. Meta Platforms experienced rapid swings after announcing plans to raise US$35 billion through a stock sale and the potential to issue an additional US$60 billion via a new class of shares. Meta’s shares initially fell more than 2%, then rallied before settling down about 0.2%.

Meta said Nvidia, Advanced Micro Devices and Broadcom have indicated they may buy a combined US$5 billion of stock in the offering, a move analysts say signals demand from firms that stand to benefit from increased AI investment.

Concerns about the cost of borrowing to build data centres and to buy chips kept AI-related stocks choppy. Elon Musk warned on his social platform X that many companies that rent AI computing power face severe pressure from tighter credit conditions:

“guppy-level death and consolidation.”

SpaceX, which operates the xAI business, swung between losses and gains after agreeing a deal valued at about US$40 billion with an Apollo Global Management-managed entity to lease AI computing capacity. Smaller AI-infrastructure names also showed wild moves: CoreWeave dropped 5.5% at the open and later flipped to a gain of 5.1%.

Earnings from Alphabet and Microsoft are due on Wednesday, with Amazon reporting on Thursday; together with hundreds of other quarterly reports this week, those results will be watched for signs of whether corporate spending on AI is producing returns. Roughly one out of every three stocks in the S&P 500 is scheduled to report results this week.

In fixed income and commodities, the yield on the 10-year US Treasury eased to 4.98% from 5.00% late Friday, down from over 5.30% earlier this month. The two-year yield nudged up to 4.71% from 4.69%. Brent crude briefly fell toward US$109 a barrel in early trade before returning to about US$111.40, below the near US$120 peak seen in March.

Markets outside the US were mixed: Brazilian shares weakened after Luiz Inácio Lula da Silva won re-election, French bond yields eased and the CAC 40 gained 0.8%. Investors are also watching policy decisions from the European Central Bank and the Bank of Japan later this week.

Verizon fell 2.8% despite reporting stronger-than-expected summer profit after revenue missed forecasts, illustrating how profit and sales growth are being parsed closely by investors as corporate reports roll out.