Any changes in short positions have to be notified to the FCA by 3.30pm the following day. They then release a spreadsheet, usually around 4.30pm with the short position changes from the previous day.
Stanley, if Tullow were entering the FTSE250 after a quarterly rebalance then it would be the 22/3. However, as they are directly replacing another company that has been removed from the FTSE250 then its effective as of today as per the RNS.
'Rebalance Effective Date The FTSE UK Index Series is reviewed on a quarterly basis in March, June, September and December. Any constituent changes will be implemented after the close of business on the third Friday of the review month (i.e. effective Monday).'
"I will endeavour to post in more detail at some point with figures to illustrate my points in respect of net debt reduction and the underlying value of the company."