Entrepreneur Tier 1 visa

Have 2 questions about Entrepreneur Tier 1 visa.

1) I understand I have to have £200,000 cash available to invest. But does this amount have to be in a UK bank in GBP at the time of application or can the funds still be in a US bank in USD equivalent? For example, would $300,000 in Bank of America be okay?

2) is investing in a common stock of some British company qualify as an "investment in a UK business"? For example, if I buy £200,000 worth stock of Marks & Spencer, or British Airways, or Barclay, would that do?

Have 2 questions about Entrepreneur Tier 1 visa.

1) I understand I have to have £200,000 cash available to invest. But does this amount have to be in a UK bank in GBP at the time of application or can the funds still be in a US bank in USD equivalent? For example, would $300,000 in Bank of America be okay?

2) is investing in a common stock of some British company qualify as an "investment in a UK business"? For example, if I buy £200,000 worth stock of Marks & Spencer, or British Airways, or Barclay, would that do?

What you want to do is the Tier 1 Investor visa. The Investor visa needs at least 2 million pounds.
https://www.gov.uk/tier-1-investor/overview

Have 2 questions about Entrepreneur Tier 1 visa.

1) I understand I have to have £200,000 cash available to invest. But does this amount have to be in a UK bank in GBP at the time of application or can the funds still be in a US bank in USD equivalent? For example, would $300,000 in Bank of America be okay?

2) is investing in a common stock of some British company qualify as an "investment in a UK business"? For example, if I buy £200,000 worth stock of Marks & Spencer, or British Airways, or Barclay, would that do?

As Sirius has pointed out, you need to have 2million gbp available for the Tier 1 Investor visa if you want to invest in that way.

The Entrepreneur visa is for those that want to start their own business in the UK.

You can apply for a Tier 1 (Entrepreneur) visa if:

    you want to set up or run a business in the UK
    you’re from outside the European Economic Area (EEA) and Switzerland
    you meet the other eligibility requirements
 

https://www.gov.uk/tier-1-entrepreneur/overview