Introduction Cost of lost labour input in Finland exceed 24 billion € per year. The aim of the study was to find out the content and processes of work ability management and the factors that make it productive. Information of a 20 financial units from Finnish companies employing 600–11 500 were collected from the period 2008 to 2013.

Methods The data on personnel, business activities, investments in work disability prevention and the costs of work disability were obtained from the companies and their occupational health care. The practices, structures, resources, and processes of work ability management, as well as internal and external co-operation were investigated through questionnaires and group interviews of the top management, HRM, supervisors, and employee representatives. We used the case descriptions, the complete mixed method data sets as a basis of the qualitative comparative analysis.

Results The companies increased investments into work disability prevention during follow-up by about 0.25%–1.5% of the payroll. Work disability costs per person-year decreased in about half of the participating companies and their units. In relation to payroll, the change in work disability costs in the studied organisations was −2% to 1.5%. From 2009 to 2013, and from 2010 to 2013, five and nine companies, respectively obtained a net benefit from their investments into work disability prevention. The reasons for the reduction in work disability costs were:

• the dismantling of barriers to co–operation,

• the visibility in practice of the strategic goals of work ability management,

• the way in which the work disability management measures focused on the main work disability risks, and

• the facilitation of multi–actor co–operation through co–ordination and the flow of information.

Discussion Companies that succeeded in managing changes and in maintaining the structures, activities and co-operation of these operations received more net benefits than those whose management of operations was disturbed by, for example, operational restructuring, or a significant person leaving HRM, the occupational safety organisation or occupational health services.