An additive to enhance the activity of an FCC catalyst containing zeolite and matrix components comprises zeolite microspheres having a novel morphology comprising a macroporous matrix and crystallized zeolite freely coating the walls of the pores of the matrix. The additives formed from microspheres containing a metakaolin and kaolin calcined through its exotherm, the latter calcined kaolin being derived from a kaolin having a high pore volume. Kaolin having a high pore volume can be a pulverized ultrafine kaolin or a kaolin which has been pulverized to have an incipient slurry point less than 57% solids.