S&P 500 top movers: Energy shares fuel the rally on Monday

• S&P 500 Index rose to a fresh 10-day high at the start of the week.
• Major energy stocks post impressive gains on Monday.
• S&P 500 Healthcare Index underperforms ahead of Tuesday's presidential debate.

Wall Street's main indexes started the new week decisively higher and the S&P 500 Index (SPX) touched its best level in 10 days at 3,359. As of writing, the SPX was up 1.8% on the day at 3,357.

S&P 500 top movers

Risk-sensitive energy stocks seem to be capitalizing on risk flows on Monday with the S&P 500 Energy Index gaining more than 3%. Among the top energy stocks, Devon Energy Corp (DVN: NYSE), Cimarex Energy Co (XEC: NYSE) and Diamondback Energy Inc (FANG: NASDAQ) are up 13%, 6.75% and 6.5%, respectively. 

Meanwhile, Boeing Co (BA: NYSE) shares are gaining 6.3% at $165.87 after Alembic Global Advisors announced that it upgraded the stock to "overweight" from "neutral".

On the other hand, ahead of the first presidential debate on Tuesday, health-care stocks are suffering losses. US President Donald Trump's Supreme Court nominee's, Amy Coney Barrett, stance on the Affordable Care Act will likely come up on Tuesday as 'The Supreme Court' is one of the topics to be covered during the debate.

At the moment, Regeneron Pharmaceuticals Inc (REGN: NASDAQ), Alexion Pharmaceuticals Inc (ALXN: NASDAQ) and Universal Health Services Inc (UHS: NYSE) share are down between 1.4% and 1%.