25 Pesos Águila - 1/4 oz Gold Bullion

The Águila series was introduced in 1991 as Mexico's answer to the Krugerrand, the Maple Leaf, and the American Gold Eagle — a direct play for the international bullion market at a moment when investor demand for fractional gold was expanding rapidly. The 1/4 oz denomination targets buyers who want gold exposure without committing to a full ounce, and Mexico's mint has produced the series with consistent .999 fineness rather than the .9167 alloy used in their older 50 Peso Centenario.

The 1998 date falls within a period of relative production stability, after the peso crisis of 1994–95 had shaken confidence in Mexican financial instruments and ironically driven renewed domestic interest in hard assets.