You may experience cases where a Contract Option is not enabled for short-selling. In such cases you will receive the following error message: "You are selling contracts you do not own or trying to close more than you currently hold. Check you are trading from the correct sub-account and have no existing orders to sell the instrument."
This issue is connected to the risk rating of the Contract Option. If the risk rating of a Contract Option is 6, then it is not possible to short-sell it under any circumstances. You will always be able to find the the risk rating of an instrument in the Trading Conditions under Instrument.
The risk rating is determined by Saxo Bank with risk rating 6 being the lowest rating possible. A significant part of the risk depends on the market capitalization, liquidity, volatility, country of incorporation, industry and M&A Activity of the underlying instrument.