The International Union for Conservation of Nature (IUCN) has a Bumblebee Specialist Group which is focused on assessing the conservation status of the c. 260 species within the genus Bombus.  If you follow the link above you can find out more information about the group and a PDF of the most recent annual report for 2015, plus past reports for 2012-2014.

The work of specialist groups such as this is vital for providing evidence as to the true picture of how the world’s pollinators are faring, and what can be done to reverse local and regional declines in their diversity and abundance.