Investing.com - Citi Research sees more gains for the U.S. stock market but it is likely to come with higher volatility and bigger corrections.In a letter to clients, the Wall Street firm said higher interest rates and a slowdown in global growth were the biggest risks for stocks.Citi sees global equity markets rising 8%, led by Europe with a 13% gain.The firm advised clients to "judiciously buy on dips," particularly the bigger ones.The U.S. stock market has suffered two corrections since hitting an all-time high in late January.