dbSet = _corpDbContext.Set(Type.GetType(typeName, true));
 var result = dbSet as IEnumerable<ObjectNSI>;

public class Initiator: ObjectNSI
    {
        [DataMember]
        public Guid IdStockCompanyAuthority { get; set; } // IdStockCompanyAuthority
        [DataMember]
        public int IdStockCompanyAuthorityType { get; set; } // IdStockCompanyAuthorityType
        [DataMember]
        public Guid IdUl { get; set; } // IdUL
        [DataMember]
        public int? IdPeriod { get; set; } // IdPeriod
        [DataMember]
        public string StockCompanyAuthorityName { get; set; } // StockCompanyAuthorityName
    }

 [DataContract]
    public class InitiatorQuestion : ObjectNSI
    {
        [DataMember]
        public int IdIniciatorQuestion { get; set; } // IdIniciatorQuestion (Primary key). 
        [DataMember]
        public string IniciatorQuestionName { get; set; } // IniciatorQuestionName.
        [DataMember]
        public bool? IsIniciatorQuestion { get; set; } // IsIniciatorQuestion
        [DataMember]
        public bool? IsIniciatorCorporateAction { get; set; } // IsIniciatorCorporateAction
        [DataMember]
        public int? IdIniciatorUnique { get; set; } // IdIniciatorUnique. 
        [DataMember]
        public int? IdCorporateActionType { get; set; } // IdCorporateActionType
    }