Automated Customer Account Transfer Service - ACATS
  
After you make your first billion or so, you’ll probably have lots of different types of assets (stocks, bonds, hedge funds, weird exotic pets) and you’ll work with different banks and brokerage firms as you juggle all that stuff. Each time you want to transfer an asset from one bank or brokerage company to another, there’s lots of paperwork to fill out (ah, the problems of the rich).
To help you with that, the National Securities Clearing Corporation (NSCC) created ACAT, a system that allows for easier transfer of assets between accounts and financial institutions. Hopefully, the relative ease of the system will give you more time to actually spend all that dough...like to go lunching in Bora Bora or diamond tossing in Ibiza.