The Dow Jones, which tracks 30 of the biggest USA listed companies, has hit new records several times over the last month on expectations of strong company profits and hopes that President Donald Trump will win backing for his tax cut plan.
"We continue to see solid numbers above expectations, stability in terms of economic growth and global growth", said Omar Aguilar, chief investment officer for equities at Charles Schwab Investment Management.
The financial index .SPSY jumped 0.5 percent, led by bank stocks that were recovering from recent post-earnings losses.
The Nasdaq added 0.56, reaching 6,624.22 at the session's end, while the S&P 500 set a new record of 2,561.26 - gaining 1.9 on the day. Shares of Anthem were up 1.9%, while shares of Tenet Healthcare were up 5.3%.
The S&P and Nasdaq also hit record intraday highs on Wednesday but traded in narrow ranges.
Chipotle Mexican Grill CMG.N slipped 1.85 percent after Bank of America Merrill downgraded the company's stock to "underperform" and slashed its price target by $105 to $285. On the Nasdaq, 1,569 issues rose and 1,159 fell.