Chandra observation of luminous and ultraluminous X-ray binaries in M101

X-ray binaries in the Milky Way are among the brightest objects in the X-ray sky. With the increasing sensitivity of recent missions, it is now possible to study X-ray binaries in nearby galaxies. We present data on six luminous sources in the nearby spiral galaxy M101 obtained with the Chandra ACIS-S. Of these, five appear to be similar to ultraluminous sources in other galaxies, while the brightest source, P098, shows some unique characteristics. We present our interpretation of the data in terms of an optically thick outflow and discuss implications.