America's manufacturing sector is expected to rebound in 2025, which could significantly boost the stock market, particularly the S&P 500, according to Bank of America strategist Ohsung Kwon. The sector, having contracted for most of the past two years, is projected to see growth starting in April, driven by improving small business optimism and increased orders for 2025. With half of the S&P 500's earnings tied to manufacturing, this revival could enhance earnings growth and stock prices, despite expectations for more muted returns compared to 2024.