When his partner Nathan Ingram is killed with a bomb, Harold Finch decides to fake his own dead to protect him (and his fiancée). Despite he is presumed dead as well, he still owns a fortune and several companies.
How did he manage that?
Update: My theorie is that when Harold decides to fake his own death, he gains some time before anyone notices that he's "dead" due to the chaos of the explosion. In this time he could have setup some front companies and manages that these inherit his fortune (he's a genius hacker after all ;-)). Is there any evidence for this?