Simplify the following text for a Grade 11 native English-speaking person.
Original: Timothy Franz Geithner ( pronounced \/ Ë É aÉ tnÉ r \/ ; born August 18 , 1961 ) , is the 75th and current United States Secretary of the Treasury , serving under President Barack Obama .
Simplified: Timothy Franz Geithner ( ; born August 18 , 1961 ) is an American economist , banker , and civil servant . He is the 75th and current United States Secretary of the Treasury , serving under President Barack Obama .