Capital that is mine getting a lift with investment from America (6)
I believe the answer is:
taipei
'capital' is the definition.
(capital of Taiwan)
'that is mine getting a lift with investment from america' is the wordplay.
'that is' becomes 'ie' (short for Latin 'id est', 'that is').
'mine' becomes 'pit' (down the pit).
'getting a lift' says the letters should be written backwards (in a down clue, letters go up).
'with' indicates putting letters inside.
'investment from america' becomes 'a' (I can't explain this - if you can you should give a lot more credence to this answer).
'ie'+'pit'='iepit'
'iepit' back-to-front is 'tipei'.
'tipei' enclosing 'a' is 'TAIPEI'.
Can you help me to learn more?
(Other definitions for taipei that I've seen before include "Capital of the Republic of China" , "Capital of Taiwan" , "Asian city" , "foreign capital" , "Taiwanese capital" .)