Abstract: A self-clinching nut fastener, which may be used as a pierce nut, having a central cylindrical pilot portion, an annular flange portion surrounding the pilot portion, having a generally flat annular panel-supporting end face and an annular groove defined in the flange end face surrounding the pilot. The bottom wall of the groove includes a projecting convex annular protuberance which extends circumferentially around the pilot and radially from the pilot to a midportion of the groove bottom wall spaced from the groove outer wall and the groove outer wall is inclined inwardly toward the pilot to define a restricted opening to the annular groove. The installation apparatus includes a die button having a projecting annular clinching lip configured to be received within the nut groove.