Apple and Google-parent Alphabet have notched new closing highs ahead of big tech earnings season. Four more of the so-called Magnificent Seven could soon join them.

Apple on Monday surpassed Microsoft to become the second largest company in the U.S. by market capitalization, following an upgrade from a Wall Street analyst and data showing strong sales of its new iPhone 17 range. Alphabet also set a record close with analysts turning positive on the returns on the company's artificial intelligence investments.

The Mag 7 companies are expected to report an average of around 15% in year-on-year profit growth for the third quarter, according to FactSet. Closely grouped within striking range of new highs are Microsoft, Nvidia, Meta Platforms and Tesla. It's only Amazon, of the group, that isn't close a record.

For chip maker Nvidia, the previous high is hardly a distant memory. The stock closed at a record of $192.57 on Oct. 9, compared with $182.64 on Monday.

Microsoft closed at a record of $534.76 in early August, shortly before Meta set its own record of $789.47. Both could potentially surpass those levels with relatively small moves on their earnings reports -- Microsoft was up 0.1% in premarket trading Tuesday at $517.06 and Meta was gaining 0.6% to $736.37.

Nvidia is expected to report its third-quarter earnings in November, after the late-October reports from the rest of the tech companies. Its own performance will likely partly depend on whether Microsoft and Meta convince the stock market that big spending on AI is powering returns.

"A big part of the Magnificent 7's rise to dominance has been their history of running asset light, low capex intensity business models. However, that characterization is now changing," said Jason Pride, chief of investment strategy & research at Glenmede. "The Mag 7's rising capex as a share of assets shows they are now more capital intensive than any top 7 stocks since at least the early 1990s, and that spending is expected to continue trending higher around the buildout of AI capabilities."

Tesla has followed a very different trading pattern from its Mag 7 fellows but is also now closing back in on its previous peak of $479.86, reached in December last year, powered by excitement about its robo-taxi and robotics technology. The stock was down 0.3% at $446.12 in premarket trading. It reports earnings later this week.

The relative laggard is Amazon.com, which is a little further off its own record close of $242.06, set in February this year. The e-commerce and cloud-computing company was shrugging off an Amazon Web Services outage that took down many major internet services on Monday to climb 0.5% to $217.52 in the premarket.