Quote from jeb9999:
There are at least 5 banks. Call IB and ask them which ones.
From IB Security FAQs:
"In order to reduce exposure to any single counterparty, these segregated customer-benefit accounts are spread across multiple large banks (at least five separate banks as of March 2008), federally-approved clearinghouses and federally-approved AAA rated money market funds -- all subject to periodic review by IBâs senior management. All investments are in federally-approved, liquid investments such as top-rated federal government securities and related instruments. "