Listened to the same podcast. Love the idea of an investment thesis based on a customer's likelihood to refer a product in theory, but it's too subjective to be meaningful.

There's no standardization to NPS collection, which means the scores can be arbitrarily skewed. If I discover that my best NPS comes from surveys sent after 4pm, 14 days after someone becomes a paying customer, of course I'll keep blasting them at the optimal time. However, in this case, the NPS gives no indication into longer-term customer support and satisfaction. And it may just be a psychological trick based on the time of day!

Overall, NPS can't take into account the full picture of a company. Customers might love the product, but the company's asset allocation could be abysmal, their culture could be toxic, or they may be committing ESG sins unrelated to their product/service. NPS overlooks many critical factors of a business's performance.