What is the ruling on the "Watani" program for Saudi stock installment plans at Al-Rajhi Bank?

It is clear that Al-Rajhi's "Watani for Share Financing or Installment" program is based on murabaha in shares, where the bank buys the shares desired by the client and then sells them to him in installments. It is permissible to participate in this program, provided that only shares of pure companies are purchased, and mixed shares are avoided, based on what Dr. Muhammad bin Saud Al-Osaimi stipulated regarding the permissibility of purchasing pure shares from Al-Rajhi on credit with repayment at a profit.