U A Nasdaq stock symbol specifying that the issue is in units. Investopedia Says: Nasdaq-listed securities have four or five characters. If a fifth letter appears, it identifies the issue as other than a single issue of common stock or capital stock. Related Terms: Nasdaq Stock Symbol U A Nasdaq stock symbol specifying that the issue is in units. Investopedia Says: Nasdaq-listed securities have four or five characters. If a fifth letter appears, it identifies the issue as other than a single issue of common stock or capital stock. Related Terms: Nasdaq Stock Symbol |