英语翻译I/We undertake to pay the sum of US$××× in cash for the

%5 of the total stock of your company.(占 .可以翻译成太多种了,看上下文了.)
I/We undertake to pay the sum of US$××× in cash for the share(s) applied upon allotment of the share(s)
该款项已经按照协议约定足额支付至贵公司指定账户
The full payment to the designated account of your company has been done according to our mutual agreement.

for 5% of the total stock of your company （我建议你下载“有道词典”使用，它很方便，不仅可以中译英，英译中，且可译日文！）

For 5% of the total stock of your company.

occupy 5 percent of capitalization of your corporation

占贵公司总股本的5％
account for 5% of the total share capital of your company
该款项已经按照协议约定足额支付至贵公司指定账户
The payment has been transfered/wired/remitted to the assigned account of your company in a lump sum as per the agreement.

For 5% of the total stock of your company.