Within the Finance Committee, he was the CDU/CSU parliamentary group’s rapporteur on Germany's Transparency Directive Implementation Act (Transparenzrichtlinie-Umsetzungsgesetz, TUG), among others.

During his time in office, he led the talks with his Austrian counterpart Josef Proell in 2009 about Austria nationalizing Hypo Alpe-Adria-Bank International, a local unit of BayernLB, after heavy losses tied to loans in Southeast and Eastern Europe had driven the overextended lender to the brink of collapse.

[2][3] In the negotiations to form a coalition government following the 2009 federal elections, Fahrenschon was a member of the working group on taxes, national budget and financial policy, led by Thomas de Maizière and Hermann Otto Solms.

[4] In October 2011, it became known that both Fahrenschon and Steffen Kampeter, Parliamentary State Secretary at the German Finance Ministry would be seeking the presidency of the DSGV after incumbent Heinrich Haasis stepped down.

[6] He later sought to limit the remaining aspects of a European banking union, namely a joint resolution fund and central supervision of all the region’s lenders.