For a finite non-empty set X, let \({{{\,\textrm{Ext}\,}}(X)}\) denote the set of all posets with carrier X, ordered by inclusion of their partial order relations. We investigate properties of posets \(P \in {{{\,\textrm{Ext}\,}}(X)}\) for which no lower cover or no upper cover in \({{{\,\textrm{Ext}\,}}(X)}\) has the fixed point property. We derive two conditions, one of them sufficient for no lower cover of P having the fixed point property, the other one sufficient for no upper cover of P having the fixed point property. If P itself has the fixed point property, the conditions are even equivalent to the respective total lack of lower or upper covers with the fixed point property. We use the results to confirm a conjecture of Schröder.
