Knotel and insurance startup Rhino didn't disclose its CEOs were brothers when it struck a complex financial deal. Now a key partner could be on the hook as Knotel scrambles to pay bills, slashes staff, and plans to shed portions of its portfolio.

· Flex-workspace firm Knotel sourced surety bonds from startup Rhino that cover the hefty security deposits due for two of its office leases if Knotel abandons the commitments. 
· But Rhino did not disclose to reinsurer Knight Re that its cofounder and CEO is the younger brother of Amol Sarva, the CEO of Knotel, raising a...