SPX is realizing 12.4 vol and the options market is only pricing 11.3

At Friday's close, one month SPX implied vol sat at 11.3 while the index has realized 12.4 over the past month. Implied is what options cost in vol terms, realized is how much the index actually moved. The spread between them is negative by about a point, which is unusual for the index. That spread is normally positive on SPX. Option sellers usually collect implied above realized, and that gap is the whole premium selling edge. Right now buyers of one month index options are paying slightly less than recent movement would justify. This is not a case of realized spiking into sleepy options. Realized vol has been falling all summer, from 15.2 at the start of July to 12.4 on Friday. Implied has simply fallen faster. IV rank on SPX is 6 out of 100 and the one year percentile is 10. In plain terms, implied vol has closed higher than this on about 90% of days in the past year. VIX finished Friday at 14.25. The curve is telling a story too. The next two weeks of expirations carry single digit at the money vols, from 5.5 out to 8.9, while 60 day implied sits at 13.1. Next week's expected move works out to about 0.9%, roughly 70 SPX points. The market is pricing calm now and more movement into the fall. None of this predicts a selloff. Cheap options can stay cheap, and realized can keep grinding lower underneath implied. It does mean index short premium currently starts from a negative spread instead of a positive one. For those of you selling SPX or SPY premium here, are you sizing down, going further out, or treating this as business as usual?