This thesis examines the stock market price variations associated with physical asset expenditure announcements in Australia. With the exception of the study of Chen and Ho (1997) in Singapore, most capital expenditure studies in other markets investigate the announcement effects associated with changes in budgeted capital expenditures. The fact that there is almost never any firm level capital budget announcement in Australia presents a unique opportunity to examine individual physical asset expenditure announcements. ¶ Three primary hypotheses pertaining to growth opportunities, free cash flow theory, and the capital market monitoring argument are developed and tested. These arguments are formulated to explain the abnormal return variations associated with physical asset expenditure announcements. The growth opportunities hypothesis posits that the abnormal returns at physical asset expenditure announcements are positively related to a firm's growth opportunities. Both free cash flow theory and capital market monitoring hypothesis postulate that the abnormal returns at physical asset expenditure announcements are negatively related to a firm's free cash flow, and cash flow respectively. Other control explanators are incorporated from the merger and takeovers literature. ¶ Event study methodology is used to examine the abnormal returns associated with physical asset expenditure announcements. Two sets of data, intraday and daily, are used to investigate the market reaction. Intraday returns are calculated on a time-weighted approach and two methods are used to calculate intraday abnormal returns. The first method defines abnormal returns as the difference between actual returns and market returns. The second method defines abnormal returns as the difference between market-adjusted returns and market-adjusted returns on a control portfolio. Daily abnormal returns are calculated using the market model. ¶ Both univariate and multivariate analyses provide strong support for the growth opportunities hypothesis. The results suggest the quality of firms' growth opportunities is the key variable determining the direction and magnitude of the abnormal returns at announcement. Support for the capital monitoring argument and the free cash flow theory is mixed, generally with a lack of support. The free cash flow variable is found to be significantly negatively related to abnormal returns, only when a finer dummy is used in the multivariate regression. All other control variables are found to be insignificant in explaining the stock market variations once the growth opportunities variable is included in the regression. ¶ This thesis makes the following contributions. First, this thesis presents the initial empirical evidence concerning physical asset expenditure announcements in Australia. Second, the thesis shows that the quality of a firm's growth opportunities is the key factor in determining the direction and magnitude of abnormal returns around physical asset expenditure announcements. These results also suggest that the equity market in Australia reacts to physical asset expenditure announcements which contain information pertaining to growth opportunities rather than the relative size of the physical asset expenditure transactions to firm value. Third, support for the capital monitoring argument and the free cash flow theory is not strong. Fourth, all other control variables are found to be insignificant in explaining the stock market variations once market to book ratio is included in the regression. Fifth, the results suggest that prior research which fails to segregate market to book ratio and free cash flow proxy into finer partitions may have possibly underestimated the market to book and the free cash flow effects.