The instrument is a form of senior debt that is paid back from the issuer's cash flows but is also secured against a ring-fenced pool of assets, such as mortgage loans, in the event of default.

这种证券是优先债务形式的一种，发行者需要用自己的现金流来偿还，并且要有一定隔离的资产池作为保障，比如说抵押贷款，以免发生不能履行责任的情况。

More and more investors are coalescing into groups, hopeful of reaching the threshold at which they can instruct mortgage-pool trustees to act against servicers (25% of note-holders in a given issue).

越来越多的投资者正聚集起来，希望能达到发动贷款池受托人来反对贷款服务者的人数底限(对某个议题来说是票据持有者的25%)。

The weighted loan-to-value ratio for the loan pool is a rock-solid 63%. These are among America's safest mortgage bets.

此外，加权贷款价值比必须保持在绝对可靠的63%，这样就能保证这些抵押贷款处于美国最安全的抵押贷款水平。