Translate the following English sentence to French:
"Speculation against the Danish krone is occurring primarily because Danish opinion polls suggest that there may be a 'no' vote in the forthcoming referendum on 28 September."
La spéculation contre la couronne danoise est principalement due aux prévisions des instituts danois de sondage d'opinion, qui prédisent un "non" lors du prochain référendum prévu le 28 septembre.