The Transaction Account Guarantee (TAG) program was created in response to the financial crisis to help settle the nerves of depositors with large bank accounts. It allows participating banks and financial institutions that have non-interest bearing accounts, like some checking accounts, to offer unlimited FDIC coverage, instead of the regular $250,000 coverage per depositor. The additional TAG insurance doesn’t apply to interest-bearing checking accounts, savings accounts, money markets, or CDs.
http://www.fdic.gov/news/board/rule2.pdf