This paper reviews the theory and evidence for agency theory-based explanations for employee stock ownership plans found in the financial participation literature. The UK Workplace Employee Relations Survey 1998 is used to test whether share plans substitute for direct monitoring and individual incentives. Contrary to some predictions in the literature, individual incentives are found to be complements of share plans, while other measures of monitoring costs provide mixed results. However, it is found that monitoring costs and a wide range of performance targets explain the conjunction of stock plans and individual incentives. It is suggested that share plans are used to mitigate dysfunctional effects of individual incentives by engendering cooperation and trust, and by broadening the range and time frame of desired performance outcomes. . I am grateful to participants at the annual HRM seminar of the European Institute for Advanced Studies in Management for comments on an earlier version of this paper. Two anonymous reviewers provided some extremely useful comments and criticisms of previous drafts of this paper. 1 The literature on all-employee financial participation tends to sidestep the issue of agency costs in the relationship between owners and managers, though this is central to the literature on executive share ownership and options.