In parliamentary systems, political parties must often bargain with each other in order to form a government. Do parliamentary rules regulating government formation impact the type of government that is formed? Existing scholarship suggests that the need for an investiture votea requirement that a new government must face a parliamentary vote at some point during its formationreduces the likelihood of a minority government. This article suggests that while real-world investiture rules can vary across several dimensions, only the investiture decision rulewhich specifies the size of the majority required for a decision to be madeimpacts the propensity for parties to form minority governments. Using new data on investiture rules for 26 European countries since 1946 or the first year of democracy, we find that parliamentary democracies that have an investiture requirement are not less likely to experience minority governments than those where governments come to power without an investiture vote. However, when an absolute majority is required for a government to succeed at the investiture stage, minority governments are considerably less likely to form; absolute majority investiture rules reduce the frequency of minority governments.