Problem/goal HAL is the national open repository for documents and data from French scientists. The deposits are organized in institutional portals and collections from research units and projects. The paper analyse how grey literature is represented in the collections of French research laboratories of ten major French research universities on HAL. Research method/procedure The paper presents original empirical results from a follow-up study to former research (Schöpfel et al. 2018, 2019), based on the assessment of HAL deposits of more than 1,700 research laboratories from ten large French research universities (excellence initiative). These laboratories cover the whole range of scientific disciplines. Data on deposits (documents, records) has been extracted for each laboratory and each output type (articles, books, reports, data…) through the HAL API. This paper puts the focus on the grey part of the academic output, in particular conference papers, reports, working papers, theses and dissertations. Empirical results are provided on the percentage of grey items in HAL, on the part of open access, differences between grey document types, disciplinary specificities and institutional strategies. Anticipated results The proposed study will take our former research on HAL laboratory collections a step further, with a representative sample of more than 1,700 laboratories covering the whole range of scientific disciplines and including more document types and some categories of research data, especially image and video files. It will also make the link with a nationwide survey more than ten years ago, on the development of open access in France and on the place of grey literature in French open repositories (Stock & Schöpfel, 2009) (Schöpfel & Prost, 2010). We will present empirical data for different document types, and we will analyse their degree of openness (Schöpfel & Prost, 2014), in comparison to other, grey and non-grey resources. Our intention is to identify particular strategies of scientists, of research laboratories and universities regarding the use of the national open repository HAL. We expect to find typical strategies (or lack of strategies) on the local level of research laboratories, and we will try to assess conditions and variables that may explain these differences. We will discuss potential effects of the visibility, impact and evaluation of the laboratories' research output, and conclude with perspectives on future research. If possible (if available at the date of the conference), additional information from a survey with HAL collection managers will be included. Practical implications The results of the empirical study will contribute to a better understanding and to a consistent and informed development of open access strategies by research laboratories. They will also provide rich data for the assessment of the research output of laboratories. Related costs The study is part of the research project HAL/LO funded by GIS URFIST from 2019-2021 with 10,000 euros.