Ann: Ceasing to be a substantial holder, page-6

There's nothing sus here.

The way it works is -
1) IFL decides they want to sell and contacts Citi.
2) Citigroup takes the line of stock from IFL.
3) Citi conducts an off market book build where funds and other wholesale/sophisticated investors are invited to bid. This works to determine the clearing price of the "block".
4) Citi offloads shares to each bidder as per the allocations and subsequently no longer holds the shares and must file a cease of sub notice.

In these situations, the underlying investment bank is not taking a direction play in holding the stock, the are merely facilitation the transaction between the block seller and the multitude of buyers.

N.B I might have some small details omitted or wrong here, but the overall theme is how it works in reality. No conspiracies by the evil investment bank