The objective of the thesis is to examine the trading behaviour and characteristics of retail and institutional traders on the Australian Stock Exchange. There are three aspects of these traders that are of particular interest to this study: (1) the information content of their trades, (2) their order placement strategies, and (3) the impact of their trading on share price volatility. Trades made on the basis of private information such as those by institutional traders are found to be associated with larger permanent price changes while trades by uninformed traders such as retail traders are found to be associated with smaller changes. In addition, institutional trades are found to have smaller total price effect compared to retail trades suggesting retail traders incur higher market impact costs. In order to profit from potentially short-lived information advantage, informed traders are expected to place more aggressive orders. The analysis of the order price aggressiveness showed institutions are more aggressive than other traders. In addition, retail traders are found to be less aware of the state of the market when placing aggressive orders. The analysis of the limit order book found significant differences between the contributions of institutional and retail traders to the depth of the limit-order book, with retail standing limit orders further from the market. This is consistent with the conjecture that uninformed traders such as retail traders have greater expected adverse selection costs. The effect of trading by retail and institutional traders on price volatility are also investigated. There is some evidence that retail traders are more active and institutional traders are proportionally less active after periods of high volatility. Also, the effect of the order activity from different trader types on volatility differs depending on the measure of order activity used.

Two essays are comprised in this dissertation to explore how market friction affects the processes of price formation. The first essay investigates on both theoretical and empirical bases how segmentation of communication amongst potential lenders can influence loan contracts. Two cases are considered. The first one assumes that potential lenders can freely communicate with each other; the second one assumes that each potential lender can only observe the decisions of its predecessors. I show theoretically that the ex post observed interest rate will be higher and the probability of syndication failure will be lower if the potential lenders cannot communicate freely with each other. These predictions are confirmed by my empirical work. Using a novel proxy, relational distance, for the segmentation of communication, I show that the larger the relational distance, the higher is the loan spread and the lower is the probability of syndication failure. In addition, the relational distance is positively correlated with the probability of the existence of non-price contract terms, such as the requirement for collateral and guarantees. My conclusions are found to be robust to endogeneity issues, potentially omitted variables and alternative model specifications. The second essay focuses on the informational effects between futures market and its spot market. Intraday data are used to investigate the lead-lag relationship between the TX returns, the TX trading activity and the TAIEX stock index returns. I focus on the transmission direction and the source of information and find that there are specific lead-lag relationships between futures returns and spot returns, in addition to the contemporaneous relationship predicted by carry-cost theory and efficient market theory. The results show that futures returns significantly lead spot returns, which suggests that informed trades occur in the futures market and makes information flows from the futures market to the spot market. By distinguishing different types of futures traders and using private information, net open buy, as a proxy for futures trading activity, I found that the major source of informed trades is foreign institutional traders because their trading activity have predictive power for future movements in both spot and futures prices. In contrary, traders in the other categories carry no information about the directional changes in both spot and futures prices.