Najafi Q&A: Guarantee

Is it permissible to have a bought deal? It is an agreement when establishing a company with someone who is obligated to guarantee all the issue of shares or part of that issue. It is his pledge from the obligor to subscribe at the nominal value without consideration in return for the pledge and on the assumption that it is permissible. Is it permissible for the obligor to get fees for work he performs - other than guaranteeing - such as preparing studies or marketing shares? Also, when subscribing to a halal company, is it permissible to pay an installment of the value of the subscribed share and to defer the payment of the remaining installments? There are details on the issue?