Chi-X Europe domine le marché européen des "dark pools" A closer look at dark pool regulation. Last November, the SEC proposed a set of regulatory changes regarding trading in "dark pools," with an emphasis on the use of IOIs (indications of interest) as a means of passing information to privileged traders.
The SEC sees the practice as an impediment to market transparency. Others have claimed it perpetuates a "two-tier system," whereby only certain traders have access to complete share information. Bulle et bullish.