Nio’s stock plunged over 12% as of Thursday, hitting a historic low of HK$69.1 during the morning session. This followed the company’s report of a dismal fourth quarter, which ended with a loss of RMB 5.85 billion ($851.6 million). This marked a significant increase compared to the loss of RMB 2.2 billion a year earlier and fell short of Wall Street’s estimate of RMB 3.6 billion, according to analysts surveyed by FactSet. Gross margin also fell to just 3.9% from a relatively healthy 17.2% a year earlier, which the electric vehicle maker attributed in part to lower deliveries of an aging product lineup and rising battery costs, among other reasons. Sales rose 62.2% year-on-year to RMB 16 billion in the three months from October to December. [Nio earnings report]