His interest in behavioral theory has led Jorion to work on stock market behavior as a pricing specialist and, for a period, as a trader on the futures markets in a French investment bank. Despite, or because of, his work Jorion has become a critic of the structure of financial capitalism. He has deplored in particular the shift in accounting standards from a definition of price based on "fundamentals," i.e. "value," to "just value" equating with the speculative price (Financial Accounting Standards Board 157). He has been instrumental at reviving Aristotle's theory of price, based on the power balance between buyer and seller, and has applied it to understand our current financial systems ("Le prix").