Nothing it seems can slow down the Wall Street bull, not trade fears, not natural disasters or any other perceived market risks.

The U.S. stock market notched fresh records Thursday, with the Dow Jones industrial average and the Standard & Poor's 500 stock index both closing at new all-time highs, adding to gains in what is already the longest bull run in Wall Street history.

Investors appear to be shrugging off any worries related to the ongoing fight between the U.S. and its trading partners, including the escalating tit-for-tat tussle between President Donald Trump and China, the world's second-biggest economy. Even though Trump hit China with a 10 percent tariff on $200 billion in additional goods this week, the levy came in lower than the 25 percent Wall Street feared.

Instead, investors are focusing on an American economy that is performing well, with the help from fiscal stimulus such as tax cuts, says Lindsey Bell, investment strategist at CFRA, a Wall Street research firm. The government Thursday said the number of Americans filing for jobless benefits fell to its lowest level in 49 years in the week ending Sept. 15.

"The new highs are being driven mostly by solid economic data," Bell says. "The market seemingly priced in a much more dire situation with regards to tariffs, and given the lower-than-expected tariff rate, the market is moving higher."

At the market close Thursday, the blue-chip Dow was up nearly 1 percent, or about 251 points, to a record 26,656.98, eclipsing its prior closing all-time high of 26,616.71 from Jan. 26. The large company S&P 500 finished at a record 2930.75.

The S&P 500 is up nearly 10 percent this year, and the Dow is about 8 percent higher.

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The bullish outlook for businesses and consumers has investors again betting on U.S. companies posting strong earnings when the third-quarter profit-reporting season gets underway in early October. Analysts forecast companies in the S&P 500 stock index to grow earnings at a 22 percent clip in the July through September quarter.

Rising interest rates, which historically have been a trigger for market downturns, haven't yet caused investors to fear an economic slowdown. The Federal Reserve, which has raised short-term rates twice this year to a range of 1.75 percent to 2 percent, is almost certain to increase rates another quarter of a percentage point at its Sept. 26 meeting.

Odds for a similar-sized rate hike at the central bank's December meeting have risen to nearly 79 percent, according to CME Group data. 

Better performance from some slivers of the market that had not been faring well earlier in the year is also providing the market with a lift, says Bell. She notes that shares of industrial companies are 3.4 percent higher this month, while the materials sector and financials are up 1.5 percent and 1.3 percent, respectively. 

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While acknowledging the U.S. economy is in good shape thanks to Trump's growth-friendly policies, which "dwarfs all other issues," Greg Valliere, chief global strategist at Horizon Investments, warns the biggest risk to the market right now might be too much optimism.

"I would worry if a mood of euphoria takes hold – that's traditionally a warning sign," Valliere told USA TODAY.