Factual error: At the end of the film, Wyatt and McQuarry each take a briefcase containing $5 million dollars. $1 million dollars in $100 dollar bills (highest denomination in circulation) weighs approximately 22lbs = 110lbs for $5 million. $5 million in $100 dollar bills is also approximately 3445 cu. in. in volume. This would not likely fit in the cases they are carrying, and would not be as easy to carry as they are.
Factual error: When McQuarry transfers the money, 'Banco National de San Sebastian' appears on screen. It should read 'Nacional' and 'Sebastián'. Further on in the movie, it is spelled correctly.
Factual error: When McQuarry first sees "S" on the subway platform, the train that pulls in is supposed to be a 6 but is obviously the 42nd Street shuttle. The window rollsigns list Times Square and Grand Central as the termini, but the 6 does not terminate at Grand Central and doesn't even serve Times Square. (Also, the station where they get on is recognizable as the Times Square shuttle platform, and "S" gets off at the Grand Central shuttle platform, neither of which is served by the 6 train.). (00:05:55)
Factual error: In Madrid, S takes a taxi with a letter W on its side. In Madrid, the letters stand for the weekdays the taxi is off-duty (except for Wednesdays, which is symboled with an X). There are no weekdays spelled with a W in Spain.
Factual error: Wyatt's car drives to the Palace hotel in Madrid through Gran Via street. This centennial hotel is so famous that any driver knows it's on the opposite direction.