  Significant (marginal) detections of periodic signals have been recently
reported in 3 (4) Active Galactic Nuclei. Three of the detections were obtained
from long EUVE light curves of moderate-luminosity Seyfert galaxies; the fourth
was discovered in Chandra data from the low-luminosity Seyfert 1 galaxy NGC
4395. When compared with Cyg X-1, I find that the period is related to the
luminosity as $P\propto L^{2/3}$ rather than the expected one-to-one
relationship. This result might be explained if the QPO is associated with the
inner edge of the optically thick accretion disk, and the inner edge radius
depends on the source luminosity (or black hole mass). A discussion of
uncertainties in the period detection methodology is also discussed.
