I should read the context of the ledger more, but briefly I would interpret it as Sir John Pettus invested 20 pounds in the Virginia Company for their adventure. No reason to think he emigrated (or got his money back!). Which Sir John, the uncle?
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A couple of points / questions for the profile presentation
From https://pettusheritage.wordpress.com/2016/11/07/misinformation-on-t...
(this is the author of the recent 2 volume Pettus book, and Mike Clarke's site extracts from the books also)
"Thomasâs emigration to Virginia followed his acquittal of a murder charge in England in 1629. By 1631, Thomas had disposed of his future interest in certain estates and departed for Virginia."
[so that would suggest he was indeed the first Pettus in America and, in context with your find, may have been representing family financial interests as well]
Thomas died in Holland in 1687.
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I haven't yet found support for a title of Colonel but I've been working on cleaning up the more "upper" lines