I invested in capital markets, initially withdrawing personal account (6)
I believe the answer is:
memoir
'personal account' is the definition.
(I've seen this in another clue)
'i invested in capital markets initially withdrawing' is the wordplay.
'invested in' indicates putting letters inside.
'capital' becomes 'rome' (capital of Italy).
'initially' indicates taking the first letters.
'withdrawing' says the letters should be written backwards.
The initial letter of 'markets' is 'm'.
'rome'+'m'='romem'
'i' going inside 'romem' is 'riomem'.
'riomem' back-to-front is 'MEMOIR'.
(Other definitions for memoir that I've seen before include "Written account of events in one's life" , "Essay on a learned subject" , "Personal biography" , "Written record of personal experiences" , "Autobiography" .)