It's difficult to pinpoint the "greatest observed redshift" with absolute certainty, as new discoveries are constantly being made and measurements are being refined. However, as of our current knowledge, the galaxy holding the record for the highest redshift is GN-z11.

GN-z11 has a redshift of z = 11.09, which corresponds to a distance of about 13.4 billion light-years. This means we're seeing this galaxy as it was just 400 million years after the Big Bang, making it one of the most distant and earliest galaxies ever observed.

Important Note: Redshift is a measure of how much the light from a galaxy has been stretched due to the expansion of the universe. The higher the redshift, the farther away and earlier in time we are seeing the galaxy.