So the takeover of Shire PLC by Takeda Pharma has been completed. I thought I'd have a quick look for merger arbitrage plays in the filings.
A few familiar names in the list below. Most of these investors are listed as having an interest (presumably short) in Takeda too and I've found a couple of examples:
Millennium - 0.68% in shares, 2.28% in derivatives
York Capital - 1.51% in derivatives
Marshall Wace - 0.3% in shares, 0.7% in derivatives
DE Shaw - 0.54% in shares, 1.07% in derivatives (Takeda short here)
Davidson Kempner - 1.39% in shares
UBS O Connor - 1.03% in derivatives
HBK Investments - 0.17% in shares, 3.08% in derivatives
Elliott - 0.0002% [chuckle] in shares, 1.28% in derivatives (Takeda short here)
This is just from a quick Google. Final positions may have been high/lower. But doesn't take long to get to 10%+ interest through derivatives.