The evolution of the SED of the GRB 221009A afterglow from 0.5–55 days. The figure shows a 0.5 day X-SHOOTER spectrum, the 12 day JWST spectrum, and HST observations at 30 and 55 days. The solid and dashed lines refer to the decomposition of GALFIT estimates of the point-source magnitude and have been slightly offset in wavelength for clarity. The dashed line shows our best-fit absorbed power-law model (for a single Galactic extinction fit to our JWST spectrum). As can be seen, there is no evidence for spectral evolution between 0.5 and 12 days, indicating no significant SN contribution at this time. At later times, the uncertainty in the underlying host galaxy light dominates the HST observations and precludes drawing firm conclusions. However, it also does not support the presence of a bright SN component. The shaded gray areas show the SED of SN 1998bw at comparable epochs, representing a range of possible extinction from A _V = 4.2–4.9 mag. The dotted lines show the shape of the afterglow as determined from our JWST observations, but scaled to the other epochs. They demonstrate the possible changes in spectral shape from 0.5–55 days.