Now It's 5000+ Authors

In Nature there is a report of a paper having over 5,000 authors. As they state:

A physics paper with 5,154 authors has — as far as anyone knows — broken the record for the largest number of contributors to a single research article. Only the first nine pages in the 33-page article, published on 14 May in Physical Review Letters, describe the research itself — including references. The other 24 pages list the authors and their institutions.

This seems to be the trend.