X
Fifth letter of a Nasdaq stock symbol indicating that listing is a mutual fund.

XMI
Applies to derivative products. Quotron symbol for the Major Market Index (MMI).

X or XD
Symbol that indicating that stock is trading ex-dividend, with no dividend.

XR
Symbol indicating that a stock is trading ex-rights, with no rights attached.

XW
Symbol indicating that a stock is trading ex-warrants, with no warrants attached.