▁U . S . ▁Sec ur ities ▁and ▁Exchange ▁Commission ▁from ▁ 2 0 0 5 ▁until ▁early ▁ 2 0 0 9 . ▁Since ▁arriv ing ▁at ▁the ▁SE C ▁in ▁ 1 9 9 5 , ▁she ▁worked ▁under ▁four ▁SE C ▁Chair men : ▁Arthur ▁Lev itt , ▁Har vey ▁Pitt , ▁William ▁H . ▁Donald son , ▁and ▁Christopher ▁C ox . ▁ ▁William ▁Donald son ▁named ▁her ▁director ▁of ▁the ▁Division ▁of ▁En for cement ▁on ▁May ▁ 1 2 , ▁ 2 0 0 5 . ▁ ▁She ▁is ▁the ▁first ▁and ▁only ▁woman ▁to ▁serve ▁as ▁director ▁of ▁the ▁Division ▁of ▁En for cement . ▁ ▁Thom sen ▁is ▁known ▁for ▁her ▁role ▁in ▁the ▁su its ▁by ▁the ▁SE C ▁against ▁En ron ▁and ▁Mar tha ▁Stewart , ▁and ▁for ▁not ▁having ▁investig ated ▁Bernard ▁M ado ff . ▁ ▁She ▁succeeded ▁Stephen ▁M . ▁C ut ler . ▁ ▁She ▁is ▁now ▁a ▁partner ▁at ▁Davis ▁Pol k ▁& ▁Ward well . ▁ ▁Thom sen ▁is ▁married ▁to ▁Ste u art ▁Hill ▁Thom sen , ▁a ▁partner ▁in ▁the ▁law ▁firm ▁S uther land ▁As b ill ▁& ▁B ren nan ▁L LP , ▁whose ▁clients ▁include ▁h edge ▁funds , ▁bro ker - de al ers , ▁and ▁invest ment ▁advis ors ▁for ▁se cur ities ▁enfor cement ▁matters . ▁ ▁Career ▁Thom sen ▁received ▁her ▁A . B . ▁from ▁Smith ▁College ▁and ▁her ▁law ▁degree ▁from ▁Harvard ▁Law ▁School . ▁