The S&P 500 is poised to close at a new all-time high today for the first time since August. Here are a few things driving the trading action:

-- Another artificial-intelligence rally: Tech stocks are leading the market higher today, as are related AI infrastructure plays like Vistra (VST) and Constellation Energy (CEG). The AI trade has found some fresh momentum in recent days, nudging indexes toward new all-time highs in spite of the risks posed by a global bond selloff.

-- Bond yields and oil prices lower: Meanwhile, two trends that pose major risks to equities-climbing bond yields and rising oil prices-are moderating. Brent crude futures were down roughly 2% to less than $99 a barrel. Yields on 10-year U.S. Treasurys have also pulled back from yesterday's heights.

-- The lopsided nature of the rally is starting to worry some investors; over the last month the S&P 500's tech and communications sectors are up the most, while seven of the other eight sectors are down. "Clearly, this is not indicative of a healthy bull market," David Morrison, senior market analyst at Trade Nation, wrote in a morning note.