definiens: means ( a ) if Atlantic has a class of stock ( x ) registered under Section 12(b ) or 12(g ) o f the Securities Exchange Act of 1934 and that is p ublicly traded on a major US exchange such as the NYSE or N ASDAQ, or ( y ) traded on a major European exchange such as Deutsche Börse or the London Stock Exchange, such publicly traded common stock of Atlantic, th e value of which will be determined [ * * * ] % by the ave rage closing price for the 15 trading days immediat ely preceding the date the particular milestone event r eferenced in this Section 6.2 is achieved ; or ( b ) i f Atlantic does not have a class of publicly traded stock, the equi ty securities of Atlantic issued in its most recent venture capital financing occurring prior to the date the particula r milestone event referenced in this Section 6.2 is achieved, which will be issued to Isis at the same price per share and with the same rights, preferences and pri vileges as provided to the other investors in such financing