Complex sentence: When redemption is done pro-rata, a pool factor is useful to investors because when the outstanding principal balance is reduced pro-rata (like early redemption), the pool factor indicates how the remaining amount is adequately securitized Choudhry, Moorad, et al.
Split into simpler sentences: When redemption is done pro-rata, a pool factor is useful to investors in cases of early repayment. In this case, the pool factor is used to indicate how the remaining outstanding principal is adequately securitized Choudhry, Moorad, et al.