O

Odd lot

A block of securities bid or offered which is smaller than the standard lot size for that particular security.

Offer for sale

A method of bringing a company to the market. The public can apply for shares directly at a fixed price. A prospectus containing details of the sale must be printed in a national newspaper.

Offer price

The price at which a seller is willing to sell. The best offer is the lowest such price available.

Official list

The list of securities which have obtained a formal listing on the main market of an exchange.

Offset

The closing-out or liquidation of a futures position.

Open interest

The total number of outstanding option or futures contracts that have not been closed out by offset or fulfilled by delivery.

Open order

An order to buy or sell a security which remains in place until it is either executed or cancelled.

Open range

Price (or price range) recorded during the opening period of the market.

Open-end fund

A mutual fund with no limit to the number of shares that can be issued.

Open-outcry

A public auction method of trading conducted by calling out bids and offers across a trading ring or pit and having them accepted.

Option

A contract conferring the right but not the obligation to buy (call) or to sell (put) a specified amount of an instrument at a specified price within a predetermined time period.

Option class

All options of the same type – calls or puts – listed on the same underlying instrument.

Option series

All options of the same class having the same exercise/strike price and expiration date.

Optionspreis

German for premium. The price a put or call buyer must pay to a put or call seller for an option contract.

Optionsscheine

German for warrant.

Order book

Compiled list of orders received that are away from the current best price in the market.

Order ticket

The document on which the details of the order are manually recorded, as soon as the order is received.

Ordinary share

The most common form of share or stock. A certificate that represents share ownership in a corporation.

Out trade

A trade that cannot be reconciled in the clearing process.

Out-of-the-money

A call option is out-of-the-money if the price of the underlying instrument is lower than the exercise/strike price. A put option is out-of-the-money if the price of the underlying instrument is above the exercise/strike price.
See also In-the-money

Over-the-counter (OTC)

In the US, a market where small capitalisation stocks (and some large capitalisation stocks as well), shell companies, inactively traded and unregistered stocks trade. The pink sheets and the OTC Bulletin Board (OTCBB) are the only places left in the US where unregistered stocks trade.
See also Pink sheets