Price Discovery during Parallel Stock-Option Preopening: An Improvement or Ground for Manipulation? ‡ Shmuel Hauser** Haim Kedar-Levy*** Orit Milo-Cohen**** Key words: Manipulation; Liquidity; Pre-Opening trade; Price discovery. JEL Codes: D84, G12, G13, G14. ‡ We are thankful to Luigi Zingales, Yakov Amihud ,Jacob Sagi and participants at seminars/conferences at the IDC Herzliya IL, Surrey University UK, for helpful and insightful comments. Any remaining errors are ours. ** Chairmen of the Israel Securities Authority. Professor of Finance at Ono Academic College, and the Guilford Glazer Faculty of Business and Management, Ben Gurion University of the Negev.
[email protected] *** The Guilford Glazer Faculty of Business and Management, Ben Gurion University of the Negev, and Ono Academic College. Corresponding author: P.O.B. 653, Beer Sheva 84105, Israel.
[email protected] Tel. (972) 8- 6472-569, Fax (972) 8-6477 697. ** Ph.D. Candidate, The Guilford Glazer Faculty of Business and Management, Ben Gurion University of the Negev, P.O.B. 653, Beer Sheva 84105, Israel.
[email protected] 1 Price Discovery during Parallel Stock-Option Preopening: An Improvement or Ground for Manipulation? ABSTRACT Many stock exchanges worldwide have long suspected that manipulative orders distort informative pricing during the pre-opening trading session. Using a unique dataset, this paper is the first to explore empirically the presence of illegal manipulation based on Kyle and Viswanathan’s (2008) criteria. They render manipulation 'illegal' if both informational (prices) and transactional (liquidity) efficiencies are deprived. We compare the indicative stock market index with the options-implied index, revealing significant price differences and illiquidity patterns similar to those predicted by theoretical models of manipulation.