  We study the optical counterparts of ultraluminous X-ray sources NGC4559 X-10
and NGC4395 ULX-1. Their absolute magnitudes, after taking the reddening into
account, are $M_V \approx -5.3$ and $M_V \approx -6.2$, respectively. The
spectral energy distribution of the NGC4559 X-10 counterpart is well fitted by
a spectrum of an F-type star, whereas NGC4395 ULX-1 has a blue power-law
spectrum. Optical spectroscopy of NGC4395 ULX-1 has shown a broad and variable
HeII~$\lambda$4686 emission, which puts this object in line with all the other
spectrally-studied ULXs. Using the Swift archival X-ray data for NGC4395 ULX-1,
we have found a period of $62.8\pm 2.3$ days. The X-ray phase curve of the
source is very similar to the precession curve of SS433. The optical variation
of the counterpart (between two accurate measurements) amounts to 0.10 mag.
Analyzing the absolute magnitudes of 16 well-studied ULX counterparts one may
suggest that as the original accretion rate decreases (but nevertheless remains
supercritical), the optical luminosity of the wind becomes dimmer and the donor
star dominates. However, an observational bias may also influence the
distribution.
