capital gain selling foreign stock when record of purchase cannot be found

Hi, A question on how to calculate the capital gain of selling a foreign stock if the record of purchase cannot be found? Have contacted stock agency, their reply is that they only keep 7 years of records. So, they cannot find the record in their database. Need your help.

Hi Mou,
You would need to provide a best estimate of the acquisition costs and provide evidence of how you arrived at those figures.  
Obviously, we can enquire into your figures under the normal enquiry rules.  
Please have a look at:
 CG16600P - Capital Gains manual: introduction and computation: Valuation of assets for Capital Gains Tax: valuation procedures: post transaction valuation checks:
If you wish to apply for post transaction valuation checks using the CG34 please see:-
 Post transaction valuation checks for Capital Gains (CG34)
Thank you.