Investors in Twitter were happy to come back to the markets the day after Christmas, a typically low-volume day. Twitter stock was heavily traded and popped about three more points. Tesla stock also got a boost as the company looks to capitalize on a big overseas opportunity - one that other tech companies are noticing as well. Plus, Blackberry's slide was triggered by several big stakeholders who decided to sell out early. Prior to their cutting their stake in the handset maker the former Blackberry executives were looking to buy out the company.