  Recent observations of the high-mass X-ray binary Cygnus X-1 have shown that
both the companion star (41 solar masses) and the black hole (21 solar masses)
are more massive than previously estimated. Furthermore, the black hole appears
to be nearly maximally spinning. Here we present a possible formation channel
for the Cygnus X-1 system that matches the observed system properties. In this
formation channel, we find that the orbital parameters of Cygnus X-1, combined
with the observed metallicity of the companion, imply a significant reduction
in mass loss through winds relative to commonly used prescriptions for stripped
stars.
