What is the ruling on selling shares of a company, where each share is sold for $1500 and yields a monthly return of 300 Riyals for one year, after which these shares expire?

Perhaps the questioner erred in stating that the shares are sold in dollars and then the buyer receives Saudi riyals in installments, because this scenario clearly entails a loss. Based on the premise that currencies are homogenous, the aforementioned transaction is forbidden (haram) and is in reality a loan, not a sale, partnership, or legitimate investment; this is because the share buyer receives a fixed monthly amount, which is impermissible. If what was mentioned in the question is accurate, then the transaction involves riba al-nasi'ah (usury of delay), which is the deferred exchange of ribawi items for one another, and that is not permissible.