Theoretically, most deals can remain open for as long as you want. Rollovers and/or overnight financing will continue to apply as long as you have enough funds in your account, and the deal will remain open until you close it or until it reaches a closing limit (Negative Balance, Stop Loss, Take Profit, etc.).
But this is not always the case. For example, share deals are automatically closed if a relevant corporate event (a split, delisting, etc.) takes place.
Want to know more about corporate events, rollover and overnight financing? Check out our Trading Conditions page.