We estimate black hole masses in Narrow Line Seyfert 1 ( NLS1 ) galaxies at the basis of their X-ray excess variance .
We apply the standard approach appropriate for Broad Line Seyfert 1 ( BLS1 ) galaxies .
In general , we find that the obtained masses are by a factor \sim 20 too small to agree with values obtained from other methods ( reverberation , stellar dispersion ) .
However , a small subset of our NLS1 objects does not require that multiplication , or the correction factor is less than 4 .
We find that this subset have a soft X-ray photon index , \Gamma _ { 0.1 - 2.4 keV } , smaller than 2 .
We thus postulate that this subclass of NLS1 actually belongs to BLS1 .