U

Underlying security

The instrument upon which traded options are listed.

Underwriting

An arrangement under which a company is guaranteed that an issue of shares will raise a given amount of cash, because the underwriters, for a commission, undertake to subscribe for any of the issue not taken up by the public.

Unit

More than one class of securities trading together as one (eg a stock and a warrant).

Unit trust

A fund which raises money from investors and invests it in a range of securities.

Unlisted securities

Securities that are not listed on an exchange.

Unlisted trading privileges

The trading of securities not listed on a US exchange but traded on that exchange at the request of a member of that exchange, and not at the request of the issuing corporation.

Up tick

A transaction executed at a price greater than the previous transaction.