gcteacher, it is all quite confusing. There are actually 4...

gcteacher,

it is all quite confusing. There are actually 4 listings.

BLT on the LSE has an ADR in the US, with the code BBL. These usually track each others movements with some currency variance. The LSE listing usually trades about 14~18% discount to the Australia listing (due to taxation dividend franking etc).

BHP listed on the ASX has an ADR that tracks the ASX listing. The code in the USA is also BHP. These track each other and can be used as a good guide.

The ADRs are actually a bundle of 2 shares. So BHP in the USA is 2 x BHP.ASX.

BHP USA listing / 2 / the A$ gives you the A$ equivalent for the ASX listing.

Same for the UK listing and BBL.

I look at these in real time and on the close to help with my trading. The only real benefit you can get from looking at the UK listing is to see what the premium or discount is to the ASX listing. If the discount is more than 18% then it may indicate sentiment is stronger than when the ASX listed stock closed.

I hope that didn't confuse you more than help you