句子翻译疑问

It is calculated by estimating the share of a company's value that can not be accounted for by its current products and cash flow.

这句话中的红色部分如何翻译恰当？以及红色部分的accountd for该翻译成什么比较恰当？这整句话的含义似乎也是有些不明白，看不懂，还求大神帮忙翻译下这整个句子