Reply to the National Accounts Questionnaire from the Office Fédéral de la Statistique (OFS), Neuchâtel. The official estimates are published in 'Le système de comptabilité nationale', OFS.

These national accounts estimates are compiled according to the ESA 2010 (“European System of Accounts 2010”), which is based on and is broadly consistent with the 2008 SNA (“System of National Accounts 2008”, Commission of the European Communities - Eurostat, International Monetary Fund, Organisation for Economic Co-operation and Development, United Nations and World Bank, 2009). The ESA 2010 has been implemented in September 2014.
Detailed methodology of Swiss national accounts could be found in the Federal Statistical Office website:

The financial intermediation services indirectly measured (FISIM) are allocated to industries and institutional sectors.
Original chain constant price estimates are referenced to 2015.