The financial crisis was shocking because so few people saw it coming, as much of the risk was hidden within complex financial instruments.

Why it matters: That likely means we have known unknowns right now, but current concerns mostly revolve around the three Cs: 1) Complacency; 2) Contagion; 3) Cyberattacks.

• Regulatory complacency: The Trump administration has rolled back certain Dodd-Frank reforms, at a time when architects of the 2008 response are asking for new protections. There's also lingering fear of the next debt-ceiling showdown ending in default — possibly resulting in mass repricing of risk across all asset classes, which in turn could precipitate a global financial panic.
• Contagion: Many economists continue to worry about emerging market debt and currencies, particularly as global financial institutions have become more interconnected.
• Cyberattacks: Big financial institutions have collapsed under their weight of market pressures or their own stupidity, but not yet because of digital arsonists inside of their networks. That could change.

Go deeper: Axios' Steve LeVine examines the coming financial contagion.