The Green Party and the Swiss People's Party laid claim to the FDP's seat. The election was complicated by the fact that Federal Councillor Moritz Leuenberger (Social Democratic Party, SP) had previously announced his intention to retire in early July 2010, but effective late December 2010; the election to his seat was initially to be held on 8 December 2010, but Leuenberger then predated his resignation so that only one electoral session would have to be held.
The SP's favoured candidates appeared to be Simonetta Sommaruga and Jacqueline Fehr, with Pascale Bruderer and Claude Janiak also considered possible candidates. Bruderer declined to seek the seat and Sommaruga officially announced her candidacy on 11 August 2010.Eva Herzog also announced her intention to stand, as did Hildegard Fässler. Fehr was also a candidate, which meant the SP nominated two of four women for the seat on 3 September 2010. There was speculation that the SP would support the Greens for the other seat, and it did not contest that seat.