This dissertation examines the impact a block trade in the underlying stock market has on options listed on that stock in the options market. There is significant debate in previous literature in regards to which market leads, and which market is preferred by informed traders. This thesis contributes to, and extends previous literature, by examining the relationship between stocks and options around block trades in a different geographical setting. Furthermore, by using a combined dataset provided by SIRCA and the Australian Securities Exchange, this dissertation is able to identify individual brokers executing block trades and analyse their activity in the options market. This unique dataset allows a direct test of the “inter-market front-running” hypothesis proposed by in prior literature. Results from this dissertation are consistent with previous literature, and indicate that the stock market leads the options market by as much as fifteen minutes. Analysis of Broker ID’s confirms that there is no evidence of any inter-market front-running.