Principally banks started trading in a really bad way.

主要是银行开始用非常恶劣的方式交易
People thought they were going to be forced to sell some of those

人们认为他们将被强迫出售证券
and we had a variety of different asset classes,

那些证券有多种类别
ranging from municipal bonds, basically changing their value.

例如市政债券它们的价值发生了变化
People said, I don't want these anymore,

持有人说我不再需要它们了
there were hedge funds that owned those on leverage,

对冲基金本以杠杆形式持有它们
so there were margin calls, which forced those securities to be sold,

当入不敷出时那些证券就被迫售出
which made them worth even less.

从而使得证券的价值更低
That got the banks even more nervous.

银行也因此更加紧张
That resulted in higher-rated securities being sold

这导致更高评估级别的证券被出售
that were also unleveraged.

即去杠杆化
What you had was panic selling of securities

恐慌性地抛售证券