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The Dow Jones Industrial Average notched its first record close above 48,000 on Wednesday, extending its gains from the previous session, as Wall Street looked ahead to a potential end to the record-breaking U.S. government shutdown.

The 30-stock Dow closed up 326.86 points, or 0.68%, at 48,254.82. The index also hit a fresh all-time intraday high in the session. The S&P 500 traded around the flatline, settling up 0.06% at 6,850.92, while the Nasdaq Composite dropped 0.26% to finish at 23,406.46.

Investors were keeping an eye on Washington, as the federal government appeared poised to reopen as soon as the end of this week. The Senate on Monday evening passed a spending bill that has since moved to the House of Representatives for a final vote. House Majority Leader Steve Scalise, R-La., told CNBC Wednesday that he expects the chamber to vote on the bill around 7 p.m. ET.

"We're in currently the longest closure in history," said Josh Chastant, portfolio manager of public investments at GuideStone Funds, adding that "it certainly would be welcome to start seeing" more economic data releases given signs of weakness in the labor market. "The focus is on getting [it] over now, and then once ultimately the terms have been decided for reopening, then maybe there's something to worry about as we think about the extension into January."

As investors prepare for an end to the ongoing shutdown, which has now entered its 43rd day, the latest moves in the market are reflecting a "kind of a bifurcated day," Chastant said, noting that investors' reopening hopes can be seen in the day's run-up in key financial names.

The Dow's outperformance was supported by those in that sector such as Goldman Sachs, JPMorgan and American Express. All three stocks had notched fresh records during the day. Other stocks whose fortunes are closely linked to the economy like Caterpillar also gained.

Bank shares across the broader market joined Goldman, JPMorgan and American Express in seeing a boost. Alongside those names, Morgan Stanley, Wells Fargo and Bank of America scored new highs. The Financial Select SPDR Fund (XLF), which tracks the S&P 500 financials sector, climbed almost 1%.

Beyond the financials, the artificial intelligence trade continued its string of volatility seen this month, as uneasy sentiment remains among investors that tech valuations could be stretched after their recent surge. Advanced Micro Devices shares popped 9%, but others like Oracle and Palantir Technologies were lower.

"There's real demand and use case for AI," Chastant told CNBC. "Earnings again have been pretty strong for technology companies, so we're not super concerned that it's a bubble at this point, just that things are richly valued."

"There's nothing wrong, in our view, of kind of trimming back, taking some gains and re-diversifying across other spots in the equity markets," he continued.

A tale of two markets emerged on Tuesday, when the Dow rallied more than 550 points, and the Nasdaq slipped. The health care sector was the top-performing sector, driven by advances in names such as Eli Lilly and Johnson & Johnson, as investors moved into parts of the market with lower valuations.