U.S equities continue defying gravity this week, with major market averages reaching new highs almost daily. On Wednesday, the S&P 500 crossed the 5000 mark for the first time, following Meta, Amazon, Netflix, and Microsoft's solid corporate earnings in the previous couple of weeks.

Wall Street professionals cheered the historical moment. George Ball, chairman of Sanders Morris, an investment firm based in Houston, is one of them, explaining what that means for Wall Street:

"The 5,000 on the S&P 500 is an important milestone for the markets, not just because it's a round number," he told International Business Times. "But because the upward direction of the S&P 500, especially after two years of significant swings, reflects the confidence that investors have in corporate America's earnings power and the strength of the economy."

Sanders sees the S&P 500 as the best single barometer of confidence in corporate America's earnings power and the economy's strength. "The direction of the S&P 500 reflects whether the economy and earnings are improving or deteriorating," he said.

"S&P 500 5,000 was driven by a resilient economy that essentially shrugged off high-interest rates, as companies have shown that they can prosper even in the face of these elevated interest rates, which haven't been this high in 40 years."

Jason R. Escamilla, CFA, founder and CIO of ImpactAdvisor LLC, is another Wall Street professional cheering now. He sees the S&P 500's crossing of 5,000 as free advertisement for U.S equities:

"As a money manager, if I had a choice between (a) a Super Bowl Commercial on the merits of long-term investing for financial independence in retirement vs. (b) the S&P 500 crossing 5000 before the weekend, and the flood of "all-time high," headlines that would follow, I'll take (b)."

Deiya Pernas, CFA, Analyst, and co-founder of Pernas Research, believes the rally in S&P 500 shares will continue: "A strong labor market, potential for softer monetary policy and the adoption and optimism around Generative AI ---- which the most impactful general-purpose technology since the internet -- will likely see the market grind higher," he told IBT.

Escamilla agrees: "Earnings are strong; wages are strong. Tax incentives on 401(k) investing are better than ever. Moreover, there's plenty of sideline cash. All this, supported by the free advertising campaign mentioned before, should keep this rally going."

Ball sees valuations remain reasonable at the current levels. "Even at the 5,000-mark, the S&P 500 is neither rich nor cheap," he stated. "The returns seen in 2023 are not likely to be replicated this year, but neither are the losses of 2022. We currently have a fair-priced market that points to normalized returns. We expect the S&P 500 to end 2024 near 5,225."

That echoes the position of Whartons' Professor Jeremy Siegel, who stated on CNBC on Thursday that U.S. equities aren't overvalued at the current levels and could gain another 7-8% this year.

Meanwhile, Ball advises investors to refrain from trying to time the market. "Investors who try to time the market die poor," he added. "Guessing when the next market pullback occurs is a fool's game, and there's a strong argument to be made that 'now' is always the right moment to put new money to work into the stock market."