As explained in Andrew Ross Sorkin’s Too Big to Fail, Morgan Stanley received a $9 billion investment from Mitsubishi UFJ in the fall of 2008 that kept the firm from collapsing.
The payment was supposed to be wired electronically, which is how most large banking transactions are done. But because it needed to be made on an emergency basis on Columbus Day, when banks in the US and Japan were closed, Mitsubishi cut a physical check. Sorkin, on his book blog, says that this may have been the largest ever written.
Below is a copy of the $9,000,000,000.00 check.