IBAN   -   International Bank Account Number. A standard numbering system developed to identify bank accounts from around the world. It was originally developed by banks in Europe to simplify transactions involving bank accounts from other countries.

Icahn Lift   -   The name given to the rise in stock price that occurs when Carl Icahn begins to purchase shares in a company. The Icahn lift occurs because of Mr. Icahn's reputation for creating value for the shareholders of the companies in which he takes an interest.

Iceberg Order   -   A large single order that has been divided into smaller lots, usually by the use of an automated program, for the purpose of hiding the actual order quantity.

ImClone IMLC   -   A publicly-traded biotechnology company marketing products in the field of oncology. The company made international headlines in 2002 after ImClone's founder and CEO Sam Waksal was indicted for attempting an insider trade of the company's stock. Shortly after Waksal's indictment, "domestic diva" Martha Stewart was also indicted for insider trading of the same stock. Stewart received information from Waksal and her own broker that Waksal had been trying to dump $5 million worth of his shares in the company on insider information, and she sold her shares on the knowledge that Waksal had tried to sell his.

Impression   -   An advertisement's (usually a banner ad) appearance on a web page. Ad space is often sold on a CPM basis.

In and Out   -   The purchase and sale of a security within a short period of time, usually on the same day.

In Play   -   A slang phrase used to describe a firm who has become a potential takeover target or has put itself up for sale. Once a bid is made, a company is put "in play" and will often attract additional bidders.

In The Penalty Box   -   When a company's stock price is in the doldrums and has yet to rebound because of poor earnings, government regulation or another reason.

In The Pink   -   An informal expression used to describe a situation in which an investor or an economy is in a good financial position. More generally, it refers to being in the best of health or condition.

Index ETF   -   Exchange-traded funds that follow a specific benchmark index as closely as possible. Index ETFs are much like index mutual funds, but whereas the mutual fund shares can only be redeemed at one price daily, the closing net asset value (NAV), index ETFs can be bought and sold throughout the day on exchanges. Through an index ETF, investors get exposure to a large number of securities in a single transaction. Index ETFs can cover U.S. and foreign markets, specific sectors, or a specific class of stock (i.e. small-caps, ADRs, etc.) but all incorporate a passive investment strategy, only making portfolio changes when changes occur in the underlying index.

Index Hugger   -   A managed mutual fund that tends to perform much like a benchmark index such as the S&P 500, which gives it the reputation of being  a "closet index fund." The majority of actively managed funds are expected to outperform the so-called average performance produced by passively managed index funds.
Also known as a "closet tracker" or "pseudo tracker".

Industry Bet   -   When an investor or portfolio manager increases (or decreases) holdings in a particular industry.

Industry Lifecycle   -   A concept relating to the different stages an industry will go through, from the first product entry to its eventual decline. There are typically five stages in the industry lifecycle. They are defined as:

i. Early Stages Phase - alternative product design and positioning, establishing the range and boundaries of the industry itself.
ii. Innovation Phase - Product innovation declines, process innovation begins and a "dominant design" will arrive.
iii. Cost or Shakeout Phase - Companies settle on the "dominant design"; economies of scale are achieved, forcing smaller players to be acquired or exit altogether. Barriers to entry become very high, as large-scale consolidation occurs.
iv. Maturity - Growth is no longer the main focus, market share and cash flow become the primary goals of the companies left in the space.
v. Decline - Revenues declining; the industry as a whole may be supplanted by a new one.

Infant Industry Theory   -   A school of thought that believes emerging domestic industries should be protected until they become stable and mature.

Inflation   -   The rate at which the general level of prices for goods and services is rising, and, subsequently, purchasing power is falling.

Inflation-Indexed Security   -   A security that guarantees a return higher than the rate of inflation if it is held to maturity.

Inflationary Psychology   -   The relationship between inflation and individuals' behavior.

Inflection Point   -   An event that changes the way we think and act.
-Andy Grove, Founder of Intel.

Intaxification   -   Slang that describes the feeling of satisfaction and joy that a tax refund creates in a person. This feeling is somewhat misguided because the tax is only refunded because the person paid too much tax during the previous year.

Intellectual Capital   -   The value of a company or organization's employee knowledge, business training and any proprietary information that may provide the company with a competitive advantage. Intellectual capital is considered an asset, and can broadly be defined as the collection of all informational resources a company has at its disposal that can be used to drive profits, gain new customers, create new products, or otherwise improve the business.  
Some of the subsets of intellectual capital include human capital, information capital, brand awareness and instructional capital.

Intelligent ETF   -   An exchange-traded fund (ETF) that employs an active investment strategy based on a broad index, such as the S&P 500 or a sector-based index. The fund may choose to exclude some stocks within the index while increasing or decreasing the percentage weighting of other stocks. Most intelligent ETFs carry higher expense ratios than standard ETFs, as well as substantially higher turnover ratios.
Also known as a "smart ETF".

Interpositioning   -   The unlawful practice of adding an extra broker/dealer as a principal on a trade, even if no service is provided. Typically, interpositioning is done as part of a mutual benefit strategy, sending commissions to the broker/dealer in exchange for referrals or other cash profit. This type of behavior occurs at the upper levels of trade between specialists and broker/dealers, hedge funds or other institutional accounts.

Invest, Then Investigate   -   An investment strategy where investors immediately purchase a stock and then do research and due diligence afterwards.

Investment Climate   -   The general economic conditions affecting the financial markets.

IOU   -   An abbreviation of the phrase "I owe you."

Irrational Exuberance   -   An infamous phrase uttered by Alan Greenspan in 1996 to describe the overvalued market at the time.

iShares   -   Index funds that trade like stocks on stock markets. Each share represents a proportion of ownership in each stock that makes up an index.

ISIN Number   -   A code that uniquely identifies a specific securities issue. The organization that allocates ISINs in any particular country is the country's respective National Numbering Agency (NNA). Stands for International Securities Identification Number.