Studies have found that when a U.S. issuer lists abroad on a foreign exchange, its shares exhibit negative abnormal returns. This negative movement may be because the market expects that the foreign listing will facilitate undetectable insider trading on the foreign exchange or other conduct impermissible in the United States.
Howson, Nicholas C. "Reverse Cross-listings - The Coming Race to List in Emerging Markets and an Enhanced Understanding of Classical Bonding." V. S. Khanna, co-author. Cornell Int'l L. J. 47, no. 3 (2014): 607-29.