Basically we sign long contracts that don't have many outs. (We also put our code in code escrow). In this way, even if we were bought by Bank 1, they would be obligated to serve the contract of Bank 2. In essence, the moment we signed one long-term deal, we became unacquirable to other FIs and are left with folks like First Data, FIS, Fiserv. Basically, we aren't selling.
Without giving away the secret sauce, could you talk a little about how you unlock growth by decoupling from the incredibly time intensive task of custom integration with each customers (Financial Insitution's) backend? Or maybe you don't and it just is what it is. I imagine you have some internal model you code to that is multi-tenant in some fashion but you are still bound by integration time with each client and then each client needs to be constantly monitored for change management basically forever. Like you need to be inserted in their change management process so they don't break your product. Eeep!