The view model *is* the list vs. the view model *has* the list.

gistfile1.cs

public class PaymentHistory : List<PaymentHistory.PaymentItem>
{
  public class PaymentItem
  {
    public DateTime TransDate { get; set; }
  }

  public List<int> YearsAvailable { get; set; }
}

public class PaymentHistory2
{
  public class PaymentItem
  {
    public DateTime TransDate { get; set; }
  }

  public List<PaymentHistory2.PaymentItem> Items { get; set; }
  public List<int> YearsAvailable { get; set; }
}