The data breach did not cause the collapse of Synapse. Synapse has been a slow rolling collapse for the past 2ish years due to horrible management. Ultimately Synapse imploded when Mercury left Synapse as a BaaS provider to partner directly with Evolve BT. The Synapse collapse definitely put Evolve into the spotlight as someone with a ton of turmoil, lack of sufficient oversight and insufficient technological governance.

Evolve is an otherwise obscure bank chartered in Arkansas but headquartered in Tennessee (a little sketchy) that has over-leveraged itself. This is why it was hit with a Cease and Desist from the FDIC. The C&D also probably contributed to them becoming a target for LockBit.

Evolve is also the underlying bank for Stripe Treasury, although to my knowledge, their have been no new partnerships with them. I have heard the number 2 thrown around. Of note, Shopify is the main person for whom this was built and uses this.

Consequently if you have submitted KYC/KYB information for Shopify, Mercury, Yotta, Dave, any other past Synapse partners, or some Modern Treasury partners your data was breached. This seems to be the primary information shared along with account and routing numbers. This becomes problematic especially as part of the check involves external account and routing numbers along with SSN of any UBOs.

Fintechs do not partner with small banks because of debit card fees but because of Dodd Frank regulations (primarily).