In general, the SNB takes its decisions (e.g. to conclude an agreement) by an absolute majority of its members which must also represent the majority of the employees. Each member has one vote.
However, if the decision should lead to a reduction of participation rights, a double 2/3 majority is required, i.e. at least 2/3 of the SNB members representing 2/3 of the employees. Moreover, the votes must come from at least two different countries. These high requirements are needed only when participation covered 25% (merger) or 50% (holding / subsidiary) of the employees. (Reduction of participation rights means a proportion of board members which is lower than the highest proportion existing within the participating companies).
A double 2/3 majority (see above) is also needed if the SNB decides not to open or to terminate negotiations.