Counter-corruption adviser to Congress Paul Massaro posted a list showing the American lobbying firms that he says are "serving Putin."
The list ranges from those dealing with trade and stock to global finances.
Massaro has urged strict sanctions that go into the heart of every possible financial tie to Moscow, even if they're front companies.
The US and UK have announced some preliminary sanctions. The EU is anticipated to take steps too, which could help target the oligarchs with money stashed through European banks.
Massaro wants to see the UK target the oligarchs, however, which some believe would put increased pressure on Putin.
Ukraine's Foreign Affairs Minister Dmytro Kuleba has said that "severe sanctions" are needed.