In the mortgage-backed securities market, whole pools refer to mortgage certificates where ownership is represented by an undivided interest in entire pools of mortgages. The term 'whole' refers to the fact that the ownership interest is undivided, as opposed to a partial or fractional interest in the pool of mortgages.

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The owner of a whole pool would generally retain all the upside potential associated with the pool. However, the downside risk is also not mitigated, since it is borne only by the investor, not shared among several participants as would be the case if they held a fractional interest in the pool.