A few references listed in this article: https://www.cloudflare.com/learning/performance/why-site-spe...
- Mobify found that decreasing their homepage's load time by 100 milliseconds resulted in a 1.11% uptick in session-based conversion
- Retailer AutoAnything experienced a 12-13% increase in sales after cutting page load time in half
- Walmart discovered that improving page load time by one second increased conversions by 2%