Hong Kong has been implementing a policy of assessment for learning to counter-balance the strong, high-stakes, summative, and examination-oriented practices of the territory. While the purposes teachers have for various classroom assessment tasks are devoted to this learning premise, their views are bounded by the social expectations of assessment for accountability. This paper reports on a study of the types of assessment tasks used by four primary school curriculum leaders, the nature of assessment for learning in Hong Kong primary school context, and their views of how the tasks could support learning improvement in the accountability era. Results indicate that, consistent with official policy, "improvement" was the dominant reason for using the eight assessment tasks discussed in interviews. However, these tasks also met the functions of "accountability," consistent with the dominant use of assessment in the Chinese context. It appears that assessment for learning in Hong Kong practice is still bounded by the need to demonstrating school quality through the preparation of students for examinations, which raises questions about the policy's validity. This paper concludes with factors that hinder a formative learning practice and recommends some follow-up strategies under this improvement-accountability tension.