So the CBOT is putting limits on position sizes ahead of expiration. See http://news.ft.com/cms/s/268a1dc0-ed85-11d9-9ff5-00000e2511c8.html I assume this action is directed at stopping customers of the exchange getting the CTD issue, rather than members trading for their own accounts. Can anyone elaborate on who was doing this? Hedge funds? Mutual funds? Prop traders?