On December 7, 1998, a format swap occurred between XHFO and XEQR-FM, with XHFO adopting the English classic hits format "Universal Stereo" that had begun in 1974, whereas "La Z" moved to XEQR. The swap was due to both formats being in close proximity to competitor stations with almost the same formats (XEQ-FM and XHDFM-FM), as well as to keep XHFO's operation in GRC's hands, since Grupo Siete tried to reclaim it after "La Z" had become Mexico City's top-rated station.