M

The fifth letter of a Nasdaq stock symbol; it signifies the issue is the firm’s fourth class of preferred shares. Securities, which have four to five letters, are listed in Nasdaq exchange have four or five letters.

When this symbol appears, the issue is being the one other than the lone issue of common or capital stock. "P" symbol identifies the issue as the firm’s first class of preferred shares, "O" indicates as the second class of preferred class; "N" being the third class; and "M" is the fourth class.