We may shorten the collateral value of securities (reduces marginability) for a variety of reasons, including:small issue size small or market capitalizationlow liquidity in the collective primary/secondary exchangesinvolvement in tenders and other corporate actionsTo see if a stock has a special margin requirement, use the Check Margin Impact feature in TWS to see the projected margin impact.Please feel free to visit the MEXEM Knowledge Base for information regarding margin rules for stocks below USD 5 and margin treatment for foreign stocks carried by a US broker.