The 16-year-old defender is regarded as one of the finest young prospects in the Bundesliga at the moment, and has attracted attention from a host of top European clubs.
Red Devils boss Sir Alex Ferguson has been credited with an interest in bringing Tah to Old Trafford, while Gunners chief Arsene Wenger was also believed to be monitoring the player's situation with a view to trying to lure him to the Emirates.
However, Hamburg have acted fast to safeguard Tah's future, securing him to a three-and-a-half year contract, that will keep him at the AOL Arena until 2016.
Without confirming either Manchester United or Arsenal's interest, Hamburg sporting director, Frank Arnesen, did say that the teenage talent had been tracked by clubs all over the continent.
"He is the greatest defensive talent we have at HSV," he told the Hamburger Morgenpost. "Jonathan is incredibly strong for his age, very quick, strong in the tackle and has good technique.
"He has everything it takes to become a good central defender. All first division clubs from Germany, Spain and England have him on their shortlist."