Tesla (up 41%) Tesla (NASDAQ: TSLA), always a battleground stock, overcame a slump at the beginning of the month to post a 41% gain, making it the S&P 500's second-best-performing stock in January. The broad-market index rose 6.2% in January as investors responded bullishly to falling inflation and signs the Federal Reserve would start slowing its interest rate hikes. Instead, a combination of bullish analyst notes, a strong earnings report from Netflix, hopes for an economic recovery, and an announcement about price hikes all seemed to give shares a boost.