In the negotiations to form a coalition government with the Christian Democrats – both the Christian Democratic Union (CDU) and the Christian Social Union in Bavaria (CSU) – following the 2009 federal elections, Solms led the FDP delegation in the working group on taxes, national budget, and financial policy; his counterpart from the CDU was Thomas de Maizière. He did not run for a parliamentary seat in the 2013 elections after having failed to be selected for the first position on the Hesse FDP state list in December 2012. His term as Member of Bundestag expired on 22 September 2013.