I believe SHAKEN/STIR was mandated only for calls originating from within the US, however, most of these fraud calls are originating over VOIP (or SIP) from outside the US.
Coinbase is a publicly listed company, with all its assets & liabilities shared in quarterly investor updates. They store all customers assets 1:1 (ie does not re-hypothecate any of customer assets)
1. When we started to specialize in a vertical and created the narrative and the product for that vertical. This is esp. true in domains with many legacy players.
2. For some reason or the other, we have always had delays in announcing our fundraising rounds: both Seed and Series A announcements were delayed by 3-6 months. The moment we announced, we got a step magnitude more inbound customers. Lesson here is to not be a perfectionist and be willing to share the company/product publicly earlier, so you can incorporate customer feedback early.
PS: If it helps provide context for (1) above, our domain is fraud prevention; and we focused on payment fraud for Fintechs/Crypto instead of going after generalized fraud prevention across all categories like ecommerce.