Fifth Third Bank
Wikipedia explains that the Fifth Third Bank's name "is derived from the names of both of the bank's two predecessor companies: Third National Bank and Fifth National Bank, which merged in 1908". But despite the fact that "[t]he bank operates 1,154 branches and 2,469 automated teller machines in Ohio, Kentucky, Indiana, Michigan, Illinois, Florida, Tennessee, West Virginia, Georgia, and North Carolina", I've managed to travel extensively in those states without ever encountering the name, until this building presented itself to us on our way to dinner last night in Toledo OH. The name seems odd at first but I guess it's memorable as a result.
Are there any other examples of names combining two ordinal numbers as the result of a merger, like the "Second Third Presbyterian Church"?