<p>Seismologists and geoscientists in general often need earthquake catalogues for various types of research. This input usually contains basic earthquake parameters such as location (longitude, latitude, depth and origin time) as well as magnitude information. For the latter, the moment magnitude <i>Mw</i> has became the most sought after magnitude scale in the seismological community to characterize the size of an earthquake. In this contribution we provide an informative account of the <i>Mw</i> content for the newly rebuilt Bulletin of the International Seismological Centre (ISC, <a href=" http://www.isc.ac.uk/"target="_blank">http://www.isc.ac.uk/</a>), which is regarded as the most comprehensive record of the Earth's seismicity. From it, we extracted a list of hypocentres with <i>Mw</i> from a multitude of agencies reporting data to the ISC. We first summarize the main temporal-spatial features of the <i>Mw</i> provided by global agencies (i.e., providing results for moderate to great earthquakes worldwide) and regional ones (i.e., also providing results or small earthquakes in a specific area). Then we discuss their comparisons, not only by considering <i>Mw</i> but also the surface wave magnitude <i>MS</i> and short-period body wave magnitude <i>mb</i>. By using the Global Centroid Moment Tensor solutions as authoritative global agency, we identify regional agencies that best complement it and show examples of frequency-magnitude distributions in different areas obtained both from the Global Centroid Moment Tensor alone and complemented by <i>Mw</i> from regional agencies. The work done by the regional agencies in terms of <i>Mw</i> is fundamental to improve our understanding of the seismicity of an area and we call for the implementation of procedures to compute <i>Mw</i> in a systematic way in areas currently not well covered in this respect, such as vast parts of continental Asia and Africa. In addition, more studies are needed to clarify the causes of the apparent overestimation of global <i>Mw</i> estimations compared to regional <i>Mw</i>. Such difference is also observed in the comparisons of <i>Mw</i> with <i>MS</i> and <i>mb</i>. The results presented here are obtained from the dataset (Di Giacomo and Harris, 2020, <a href=" https://doi.org/10.31905/J2W2M64S"target="_blank">https://doi.org/10.31905/J2W2M64S</a>) stored at the ISC Dataset Repository (<a href=" http://www.isc.ac.uk/dataset_repository/"target="_blank">http://www.isc.ac.uk/dataset_repository/</a>).</p>