Question

帮我分析一下这句子的句子成分

Where a bank has Tier 3 capital, within the limits set out in paragraph 49, which is not at present
supporting market risks, it may report that excess as unused but eligible Tier 3 alongside its standard ratio.
Where在句首是起什么作用的？within the limits set out in paragraph 49, which is not at present
supporting market risks这现两句应该是定语修饰前面的Tier 3 capital，那么最后一句是什么成分呢？

Answer 1

这是文件书写格式中常见的文体。此处 where 引导一个条件状语从句，词义与 if 同。
, within the limits set out in paragraph 49, 是插入语（状语），用以限定句子的语义解释。
which is not at present supporting market risks 是一个非限定性定语从句，修饰先行词 paragraph 49
最后一句（it may report that excess......）是这个句子的主句。由于前面从句中已提到 a bank，主句用代词 It 就可以了。