Seminar paper from the year 2010 in the subject Economics - Finance, grade: 1.3, University of Regensburg, language: English, abstract: Since Modigliani/Miller's famous theorem (1958) that capital structure is irrelevant for firm valuation, firms' capital structure choice has been one of the most significant subjects in the modern finance theory. The subsequent theoretical literature has found evidence to negate the irrelevance theorem. Most empirical studies applied a static framework and are capable to explain differences in the optimal leverage ratios across firms, using observed leverage ratios as proxies for the optimal target leverage, but do not explain observed differences in firms' leverage ratios itself. One broadly accepted reason for a firm's deviation from their target leverage ratio is the existence of adjustment costs. In the presence of adjustment costs, firms may deviate from their target leverage and find it not cost effective to adjust their leverage ratio frequently or fully within one period, even if they recognize that their existing capital structure is not optimal. This shows the need for developing and using a dynamic approach in order to examine firms' capital structure.The paper is organized as follows. Section 2 provides a brief overview of the three main theories of capital structure. Section 3 specifies the dynamic partial-adjustment model and describes the variables that may affect the target capital structure as well as the ...