Parnassus Growth Equity Fund stated in its Q2 2026 investor letter that Lumentum Holdings Inc. (Nasdaq: LITE) holds a critical position in the optical networks of AI infrastructure. As data demand grows, the market is shifting from copper-based systems to fiber optic systems. The company's components enable faster and more efficient data transmission, and it possesses competitive advantages such as deep technological expertise and high switching costs. As of September 15, Lumentum's stock price was $838.96, having risen 439.98% over the past year. The fund's Q2 return was 17.49%, outperforming the Russell 1000 Growth Index's 16.74%.