Where is the interaction between prime numbers and the praxeology of buying and selling securities?
Primes don't have anything to do with Stock Market analysis.
From the article (ha! I didn't read it, I just skimmed it, but it's not think with maths), what the researchers found, using primes, is a generalization of Benford's Law. It's this Generalized Benford's Law that can be used in Analysis.
In addition, many applications that have been developed for Benford's law could eventually be generalized to the wider context of the Generalized Benford's law. One such application is fraud detection: while naturally generated data obey Benford's law, randomly guessed (fraudulent) data do not, in general.
(OK, so the article doesn't mention stock market except for the part that is quoted in the summary, but better fraud detection would play a part in stock market analysis, yes?)