How would I extract the capitalized, 3 character group from a text string?

I have 283 rows of text of varying lengths, each with a 3 character upper
case string imbedded at any point, followed by more characters. I would like
to isolate the 3 characters of upper case text and place them in a single
column. Some examples a

iPath S&P GSCI Crude Oil Tot Ret Idx OIL Specialty - Natural Resources
UltraShort Financials ProShares SKF Specialty - Income holdings
PowerShares DB Energy DBE Specialty - Healthcare
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newwbie