Most analysts think that September's top-performing stocks could continue their ascent. September is a traditionally dicey for stocks: It's the worst month of the year for the S & P 500 , according to the Stock Trader's Almanac . Indeed, the market had a rocky start to the month, but the major averages have largely put in a strong showing after the Federal Reserve's outsized rate cut .

The three major indexes are all on pace to September higher than where they began. The S & P 500 and Dow Jones Industrial Average are both up more than 1% this month, while the tech-heavy Nasdaq Composite is on pace to advance more than 2%. With October right around the corner, CNBC Pro used FactSet data to screen for this month's top-performing stocks in the S & P 500 and find out where analysts see them going next.

Analysts forecast further upside for seven of the 10 stocks on the list. Market data below is current as of Wednesday afternoon. Constellation Energy is up more than 30% on the month, making it September's second-highest performer in the S & P 500.

Shares of the carbon-free energy producer have more than doubled this year. More than 7 out of 10 of the analysts covering the stock have assigned it a buy or overweight rating, according to FactSet. However, consensus price targets suggest a mere 2% of upside.

The company made headlines this month with the news that it would be restarting the Three Mile Island nuclear plant and sell the power to Microsoft . Microsoft will purchase elect.