Saudi Deputy Crown Prince Mohammed bin Salman has pegged the value of Aramco at $2 trillion.

RIYADH—Officials at Saudi Arabian Oil Co. have told their superiors there is a hitch in the plans to take the state-owned oil company public: It is likely worth at least $500 billion less than the government previously suggested.

The country’s deputy crown prince, who is leading a push to overhaul the economy, has pegged the value of the company known as Saudi Aramco at $2 trillion. But officials…