The Crash Of 2086 — Morris Hershman

For more than five years, the planet Rillut had been trying to bring Earth's economy to a grinding halt; it was the only certain way of ensuring the overthrow of the government of Unified Earth. Extremists from both planets planned acts of mass violence to disrupt the body politic, and it was Matt Brisbane's mission to stop them--secretly and alone! Also published under the title, Shareworld.