Solar stocks have demonstrated some of the most robust performances among various sectors since the start of the month, buoyed by favorable market conditions and positive corporate earnings. The Invesco Solar ETF (NYSE:TAN), which tracks the performance of approximately 40 solar energy companies, has experienced a significant upturn. Over the last 10 sessions, this ETF has surged by 10%, rebounding from its lowest point since July 2020. This rally is particularly noteworthy as it reflects broader investor optimism in the renewable energy sector. Several factors have contributed to this positive momentum. A notable catalyst has been the decrease in long-dated U.S. Treasury yields, which have fallen substantially since late April. Specifically, the 30-year Treasury yield dropped from a high of 4.85% to 4.63%, and the 10-year yield decreased from 4.73% to 4.50%. These declines in yields reduce the cost of borrowing and are especially beneficial for capital-intensive industries like solar energy. The sensitivity between solar stock performance and Treasury yields is strong. Solar companies often rely on significant capital to fund their expansive projects. When Treasury yields rise, so do borrowing costs. Higher interest rates increase the cost of loans for solar firms, which can reduce ...