If I understand correctly, the Planck Collaboration in this instance is exactly those hundred-something people listed in the paper, so
author = {{Planck Collaboration} and Y. Akrami and ...}
is not strictly speaking correct. It would be either
author = {{Planck Collaboration}}
or
author = {Y. Akrami and ...}
I can see how each of those solutions is not perfect: If you give only the group name, you effectively deny the people their name in the citation (although you would not give all hundred odd names anyway, so only about three out of 120 people will be mad at you, that is quite a good overall score). But if you cite only the people, the collaboration name, which is probably more widely known, will not be mentioned.
Unfortunately, biblatex and BibTeX have no notion of "a group consisting of ..." - you can either list the group name, or each member individually.
In this case you might be able to get away with
shortauthor = {{Planck Collaboration}}
but note that while the citation will look as expected, the bibliography entry will still have an incorrect "and" or "et al." if you use author = {{Planck Collaboration} and Y. Akrami and ...}.
I guess it would be ideal if you could put all individual names into the author field and the collaboration name into shortauthor. You would then have to convince your bibliography style to show both the shortauthor (collaboration name) and author (individual names) in the bibliography. Off the top of my head I know of no style that does this by default, but the modifications necessary to make biblatex do this are not too involved.
\documentclass[british]{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{babel}
\usepackage{csquotes}
\usepackage[style=authoryear, backend=biber]{biblatex}
\makeatletter
\renewbibmacro*{author}{%
\ifboolexpr{
test \ifuseauthor
and
not test {\ifnameundef{author}}
}
{\usebibmacro{bbx:dashcheck}
{\bibnamedash}
{\usebibmacro{bbx:savehash}%
\printnames{shortauthor}%
\setunit{\addcomma\space}%
\printnames{author}%
\iffieldundef{authortype}
{\setunit{\printdelim{nameyeardelim}}}
{\setunit{\printdelim{authortypedelim}}}}%
\iffieldundef{authortype}
{}
{\usebibmacro{authorstrg}%
\setunit{\printdelim{nameyeardelim}}}}%
{\global\undef\bbx@lasthash
\usebibmacro{labeltitle}%
\setunit*{\printdelim{nonameyeardelim}}}%
\usebibmacro{date+extradate}}
\makeatother
\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}
@online{planck18x,
shortauthor = {{Planck Collaboration}},
author = {Y. Akrami and F. Arroja and M. Ashdown and J. Aumont and C. Baccigalupi and M. Ballardini and A. J. Banday and R. B. Barreiro and N. Bartolo and S. Basak and K. Benabed and J.-P. Bernard and M. Bersanelli and P. Bielewicz and J. J. Bock and J. R. Bond and J. Borrill and F. R. Bouchet and F. Boulanger and M. Bucher and C. Burigana and R. C. Butler and E. Calabrese and J.-F. Cardoso and J. Carron and A. Challinor and H. C. Chiang and L. P. L. Colombo and C. Combet and D. Contreras and B. P. Crill and F. Cuttaia and P. de Bernardis and G. de Zotti and J. Delabrouille and J.-M. Delouis and E. Di Valentino and J. M. Diego and S. Donzelli and O. Doré and M. Douspis and A. Ducout and X. Dupac and S. Dusini and G. Efstathiou and F. Elsner and T. A. Enßlin and H. K. Eriksen and Y. Fantaye and J. Fergusson and R. Fernandez-Cobos and F. Finelli and F. Forastieri and M. Frailis and E. Franceschi and A. Frolov and S. Galeotta and S. Galli and K. Ganga and C. Gauthier and R. T. Génova-Santos and M. Gerbino and T. Ghosh and J. González-Nuevo and K. M. Górski and S. Gratton and A. Gruppuso and J. E. Gudmundsson and J. Hamann and W. Handley and F. K. Hansen and D. Herranz and E. Hivon and D. C. Hooper and Z. Huang and A. H. Jaffe and W. C. Jones and E. Keihänen and R. Keskitalo and K. Kiiveri and J. Kim and T. S. Kisner and N. Krachmalnicoff and M. Kunz and H. Kurki-Suonio and G. Lagache and J.-M. Lamarre and A. Lasenby and M. Lattanzi and C. R. Lawrence and M. Le Jeune and J. Lesgourgues and F. Levrier and A. Lewis and M. Liguori and P. B. Lilje and V. Lindholm and M. Lpez-Caniego and P. M. Lubin and Y.-Z. Ma and J. F. Macías-Pérez and G. Maggio and D. Maino and N. Mandolesi and A. Mangilli and A. Marcos-Caballero and M. Maris and P. G. Martin and E. Martínez-González and S. Matarrese and N. Mauri and J. D. McEwen and P. D. Meerburg and P. R. Meinhold and A. Melchiorri and A. Mennella and M. Migliaccio and S. Mitra and M.-A. Miville-Deschênes and D. Molinari and A. Moneti and L. Montier and G. Morgante and A. Moss and M. Münchmeyer and P. Natoli and H. U. Nørgaard-Nielsen and L. Pagano and D. Paoletti and B. Partridge and G. Patanchon and H. V. Peiris and F. Perrotta and V. Pettorino and F. Piacentini and L. Polastri and G. Polenta and J.-L. Puget and J. P. Rachen and M. Reinecke and M. Remazeilles and A. Renzi and G. Rocha and C. Rosset and G. Roudier and J. A. Rubiño-Martín and B. Ruiz-Granados and L. Salvati and M. Sandri and M. Savelainen and D. Scott and E. P. S. Shellard and M. Shiraishi and C. Sirignano and G. Sirri and L. D. Spencer and R. Sunyaev and A.-S. Suur-Uski and J. A. Tauber and D. Tavagnacco and M. Tenti and L. Toffolatti and M. Tomasi and T. Trombetti and J. Valiviita and B. Van Tent and P. Vielva and F. Villa and N. Vittorio and B. D. Wandelt and I. K. Wehus and S. D. M. White and A. Zacchei and J. P. Zibin and A. Zonca},
title = {Planck 2018 results. X. Constraints on inflation},
volume = {10},
date = {2018-07-17},
eprint = {1807.06211},
eprinttype = {arxiv},
eprintclass = {astro-ph.CO},
}
\end{filecontents}
\addbibresource{\jobname.bib}
\addbibresource{biblatex-examples.bib}
\begin{document}
\cite{sigfridsson,planck18x}
\printbibliography
\end{document}
![Planck Collaboration, Akrami, Y. et al. (17th July 2018). Planck 2018 results. X. Constraints on inflation. arXiv: 1807.06211 [astro-ph.CO].](https://i.stack.imgur.com/64pMf.png)
Best Answer
I took me hours to find the answer. However, I just stumbled across the following posting.
Just put the option
in the the preamble.
E.g.:
Now everything works as expected.