The "beneficial ownership register" goes beyond the current registration of corporations and shareholders by untangling ownership structures to help tax authorities track down those who are using low-tax regimes overseas to illegally reduce their tax bills. Cameron hopes that by making the data public it will put more pressure on firms and individuals seeking to hide wealth and profits.
So far Google, Facebook, Microsoft, Apple and Starbucks have all been identified as carrying out these particular business practices to keep profits high.
"For too long a small minority have hidden their business dealings behind a complicated web of shell companies - and this cloak of secrecy has fuelled all manners of questionable practice and downright illegality," Cameron will say at a conference in London later today.
Cameron will urge other countries to follow suit, but since that might mean copying one of his ideas, many countries will think twice.