研究的第一个假设是界定自愿性信息披露水平是否增加或降低公司资本成本。以前的研究表明，更大的自愿性信息披露减少信息不对称，因此降低资本成本的公司，如前所述。然而，有基姆和韦雷基亚[ 1994 ]的矛盾研究，张[ 2001 ]，表明增加的资本成本影响的披露自己所导致的信息不对称。章（2001）还提出了自愿性信息披露与资本成本的关系取决于披露水平变化原因的模型。当盈余变动、波动性冲击的变动或信息分析成本的变动所引起的变动时，披露水平与资本成本呈正相关。然而，在披露成本变动导致披露成本变动的情况下，资本成本与披露水平负相关。
The research question related to this study is whether voluntary disclosure added value for stock exchange listed companies in the UK. The value for the company is considering cost of capital. To answer for this question it is needed to formulate sub-question: first of all, it will be determine what the theories of voluntary disclosure; what is determinants for voluntary disclosure level; what is effects of voluntary disclosure; and also it is important to investigate the previous studies concerning voluntary disclosure and cost of capital.
The hypothesis will be considered during the research; however, two of them can be defined.
The first hypothesis of study is to define whether level of voluntary disclosure increase or decrease cost of capital of the company. The prior studies suggest that the greater voluntary disclosure reduce information asymmetry and therefore reduce cost of capital of the firm, as was stated before. However, there is the contradiction studies of Kim and Verrecchia , Zhang , that suggest that the increased cost of capital influenced by disclosure themselves which have lead to information asymmetry. Zhang (2001) also suggests the model when the relation of voluntary disclosure and cost of capital depends on causes variation in disclosure level. When the variation driven by earnings variability, variability of liquidity shocks, or the cost of information analysis then disclosure level and cost of capital are positively correlated. However, in the case when the variation of disclosure causes by disclosure costs, cost of capital negative related to disclosure level.