Taiwan’s financial system undergirds a $760 billion high-tech economy, but its vulnerability to advanced hacks has raised fears of a worst-case scenario: a full-blown cyberattack from China that sends its currency and markets into a tailspin.

To bolster its online defenses, government officials and financial institutions in Taipei are consulting security experts from the US Treasury Department and working with American cybersecurity company SimSpace Corp. to run simulated cyberattacks, cramming a hypothetical three weeks of digital assaults into an eight-hour drill.