The Dow Jones Industrial Average continued with its record run on Thursday, after breaching the 20,000 milestone a day earlier.
The S&P and Nasdaq also hit record levels immediately after open, before easing off their highs.
Earnings are expected to show growth of 6.8 per cent in the fourth quarter, their biggest increase in two years.
Of the 104 S&P 500 companies that have reported results so far, nearly 70 per cent have topped expectations, according to Thomson Reuters.
“Today is about earnings and part of the Dow reaching the 20,000 milestone is because of strong earnings,” said Peter Cardillo, chief market economist at First Standard Financial in New York.
“Sure, Trump’s initiatives have been an element in the rise but the fundamentals of the market remain strong.”
The post-election rally roared back to life this week following optimism over US President Donald Trump’s pro-growth initiatives and solid earnings.
Trump’s business-friendly decisions since taking office on Friday include signing executive orders to reduce regulatory burden on domestic manufacturers and clearing the way for the construction of two oil pipelines.
The S&P 500 and the Nasdaq Composite indexes also closed at record highs for the second consecutive session on Wednesday.
At 9:39 am ET (1439 GMT) the Dow Jones industrial average was up 23.98 points, or 0.12 per cent, at 20,092.49.
The S&P 500 was up 0.42 points, or 0.01 per cent, at 2,298.79.
The Nasdaq Composite was up 10.57 points, or 0.19 per cent, at 5,666.91.
Seven of the 11 major S&P sectors were International News higher, with the energy index’s 0.36 per cent rise leading the advancers.
Tech giants Intel, Alphabet, Microsoft and Starbucks are scheduled to report after market close.
Initial claims for state unemployment benefits increased 22,000 to 259,000 for the week ended Jan. 21, the Labor Department said on Thursday. However, the underlying trend remained consistent with tightening labor market conditions.
The Commerce Department will release numbers for US single-family home sales in December. The report, which is expected to show a slight dip in sales from the previous month, is due at 10 am ET.
Biogen was up 3.4 per cent at $282.51 after the drugmaker reported results.
EBay jumped 7.3 per cent to $32.46, a day after the e-commerce company reported a rise in revenue for the fourth-quarter holiday period.
Whirlpool fell 4.6 per cent to $181.50 after the world’s largest maker of home appliances posted a quarterly profit that came in below expectations.
Verizon Communications fell 1.5 per cent to $49.09 after the Wall Street Journal reported the company is exploring a combination with cable company Charter Communications. Charter was up 6.6 per cent at $330.27.
Advancing issues outnumbered decliners on the NYSE by 1,532 to 1,069. On the Nasdaq, 1,227 issues rose and 1,001 fell.
The S&P 500 index showed 40 new 52-week highs and one new low, while the Nasdaq recorded 75 new highs and four new lows.