Position limits are defined on regulatory websites and may change periodically.  Some contracts also have near-term limit requirements (near-term position limits are applied to the side of the market for those contracts that are in the closest expiring month issued).  Traders are responsible for monitoring their positions as well as the defined limit quantities to ensure compliance.  The following information defines how position limits are calculated;

Option position limits are determined as follows:

• Bullish market direction -- long call & short put positions are aggregated and quantified in terms of equivalent shares of stock.

• Bearish market direction -- long put & short call positions are aggregated and quantified in terms of equivalent shares of stock.

The following examples, using the 25,000 option contract limit, illustrate the operation of position limits:

• Customer A, who is long 25,000 XYZ calls, may at the same time be short 25,000 XYZ calls, since long and short positions in the same class of options (i.e., in calls only or in puts only) are on opposite sides of the market and are not aggregated
• Customer B, who is long 25,000 XYZ calls, may at the same time be long 25,000 XYZ puts. Rule 4.11 does not require the aggregation of long call and long put (or short call and short put) positions, since they are on opposite sides of the market.
• Customer C, who is long 20,000 XYZ calls, may not at the same time be short more than 5,000 XYZ puts, since the 25,000 contract limit applies to the aggregate position of long calls and short puts in options covering the same underlying security. Similarly, if Customer C is also short 20,000 XYZ calls, he may not at the same time have a long position of more than 5,000 XYZ puts, since the 25,000 contract limit applies separately to the aggregation of short call and long put positions in options covering the same underlying security.

Notifications and restrictions:

IB will send notifications to customers regarding the option position limits at the following times:

• When a client exceeds 85% of the allowed limit IB will send a notification indicating this threshold has been exceeded
• When a client exceeds 95% of the allowed limit IB will place the account in closing only. This state will be maintained until the account falls below 85% of the allowed limit. New orders placed that would increase the position will be rejected.

Notes:

Position limits are set on the long and short side of the market separately (and not netted out).
Traders can use an underlying stock position as a "hedge" if they are over the limit on the long or short side (index options are reviewed on a case by case basis for purposes of determining which securities constitute a hedge).
Position information is aggregated across related accounts and accounts under common control.

Definition of related accounts:

IB considers related accounts to be any account in which an individual may be viewed as having influence over trading decisions. This includes, but is not limited to, aggregating an advisor sub-account with the advisor's account (and accounts under common control), joint accounts with individual accounts for the joint parties and organization accounts (where an individual is listed as an officer or trader) with other accounts for that individual.

Position limit exceptions:

Regulations permit clients to exceed a position limit if the positions under common control are hedged positions as specified by the relevant exchange. In general the hedges permitted by the US regulators that are recognized in the IB system include outright stock position hedges, conversions, reverse conversions and box spreads. Currently collar and reverse collar strategies are not supported hedges in the IB system. For more detail about the permissible hedge exemptions refer to the rules of the self regulatory organization for the relevant product.

OCC posts position limits defined by the option exchanges.   They can be found here.
http://www.optionsclearing.com/webapps/position-limits

Account holders maintaining positions in American Depository Receipts (ADRs) should note that such securities are subject to periodic fees intended to compensate the agent bank providing custodial services on behalf of the ADR.  These services typically, include inventorying the foreign stocks underlying the ADR and managing all registration, compliance and record-keeping services.

Historically, the agent banks were only able to collect the custody fees by subtracting them from the ADR dividend, however, as many ADRs do not regularly pay dividends, these banks have been unable to collect their fees.  As a result, in 2009, the Depository Trust Company (DTC) received SEC approval to begin collecting these custody fees on behalf of the banks for ADRs which do not pay periodic dividends.  DTC collects these fees from its participant brokers (such as IB) who hold the ADRs for their clients.  These fees are referred to as pass-through fees as they are designed to be then collected by the broker from its clients.

If you hold a position in a dividend paying ADR, these fees will be deducted from the dividend as they have in the past.  If you hold a position in an ADR which does not pay a dividend, this pass-through fee will be reflected on the monthly statement of the record date in which it is assessed.  Similar to the treatment of cash dividends, IB will attempt to reflect upcoming ADR fee allocations within the Accruals section of the account statements as well. Once charged, the fee will be reflected in the Deposits & Withdrawals section of the statement with the description 'Adjustments - Other' along with the symbol of the particular ADR it is associated with.

While the amount of this fee will generally range from $0.01 - $0.03 per share, the amounts may differ by ADR and it is recommended that you refer to your ADR prospectus for specific information.  An on-line search for the prospectus may be conducted through the SEC's EDGAR Company Search tool.

This is the pertinent information traders should know about odd lot orders:

• An odd lot is a number of shares less than 100 (1-99)
• A "Round Lot" is 100 shares of stock
• Any number of shares that is a multiple of 100 is a round lot (i.e. 100, 600, 1,600, etc)
• An order for a number of shares greater than 100, but not a multiple of 100 (i.e. 142, 373, 1,948, etc) is a "Mixed Lot" (AKA PRL, or partial round lot, order)
• Odd-Lot orders are not posted to the bid/ask data on exchanges
• Odd-Lot orders are taken into the order book at the exchange they are routed to.  When the exchange is able to match an order from the other side of the book with the odd-lot, it will be filled.  This could lead to delay on execution of an odd-lot. 
• There are numerous guidelines for the routing of odd-lot orders:  Odd-Lot orders to initiate positions will not be routed to primary exchanges; Odd-Lot orders can be routed to primary exchanges, but only if the order in question is to close out a preexisting position; IB will not direct-route odd-lot orders which initiate positions to primary exchanges, therefore these type of orders should be Smart Routed so that IB's routing system can send the order to an ECN for execution.  The exception is that odd lots can be routed to NYSE/ARCA/AMEX, but only as part of a basket order or as a market-on-close (MOC) order.
• A mixed lot or PRL (i.e. 257 shares) direct-routed to NYSE/AMEX will be submitted in whole to the exchange (applies to both market and limit orders).  If the order is direct-routed to NYSE/ARCA, only the round lot portion of the order will be submitted and, if it is executed, the IB system will cancel the remaining odd-lot portion of the order.  If the order is routed via IB Smart Routing, all market centers are eligible to receive the order according to the Smart Routing logic (including NYSE/ARCA, but only for the round lot portion of the order).
• IB will not route odd-lot orders for HOLDRS.  The odd-lot portion of a PRL order for HOLDRS will be rejected by the IB system after the round lot portion of the order is executed.
• Individual exchanges may impose certain restrictions on odd lot orders, in addition to any of the restrictions mentioned above

1. Total Quantity – defines the aggregate order size (e.g., shares, contracts);
2. Trade Increment – defines the unit (e.g., shares, contracts) size for each component order;
3. Time Increment – defines the period of time (seconds, minutes or hours) between the submission of a component order and the submission of the following order;
4. Order Type – may select from market, limit or relative. A market order will be executed at the ask price and should only be used where, for example, a stock is highly liquid with significant bid-ask sizes. Limit and Relative order types require that the trader specify additional order relationships and the choices are numerous. The execution price, for example, may be specified as being relative to a fixed value, bid, ask or last price, VWAP, moving average or last trade. These choices may be increased or decreased by an offset factor and multiple conditions may be established. For example, one may wish to create a relative order type to match the bid price plus an offset factor of $0.01 and to ensure that they don’t lift the ask if the spread is $0.01, add a condition that the bid be no less that $0.02 beneath the ask price.
5. How to Operate – if the trader does not check the box titled “Wait for current order to fill before submitting next order” then orders which do not meet the price conditions will continue to accumulate in accordance with the established time increment, the unexecuted orders will be aggregated into one or more potentially sizable orders at the exchange. If this box is checked, then the more restrictive the buying conditions, the greater the likelihood that the algorithm will fall behind its schedule of buying or selling at every ‘X’ interval.  If this box is checked the trader may then check the box titled “Catch up in time”. When that box has been checked and should the algorithm fall behind, the next orders will be placed immediately after their predecessor fills until such time the algorithm has caught up.
6. Randomization – check boxes are provided to allow for a +/- 20% randomization in the time increment and a +/- 55% randomization in the trade increment. Accordingly, in the case of a 30 second time increment, this would allow for randomization of between 24 and 36 seconds between orders and in the case of a 500 share trade increment, this would allow for randomization of between 200 and 800 shares (rounded to the nearest round lot) per order. Randomization serves to minimize the likelihood of others detecting your order.
7. RTH – a check box is provided which will allow the order to be filled outside of regular trading hours.
8. Take up Offer Size – if a limit or relative order type is selected, the trader may input an order size which if bid (in the case of a sell order) or offered (in the case of a buy order) the trader would be willing to take in its entirety, up to the remaining portion of the total order quantity (satisfies the price conditions).

1. Price Range - traders may specify a price range outside of which they do not want to buy the stock;
2. News – the trader may stop the algorithm for some period of time if there is news on the stock, for example;
3. Position - traders may stop the algorithm based upon their position in the stock; For example, a trader running multiple algorithms one to buy the stock and another to sell in an attempt to trade the stock back and forth for a profit may decide to suspend one side if the position becomes substantially imbalanced;
4. Stock Path – a trader, for example, may wish to suspend the algorithm if a given moving average, say the 10-minute VWAP is not at least as high as another average, say the 50-day moving average. This feature enables you to set up algorithms to trade chart points even when you are not looking at the chart at that moment;
5. Stock Path for Multiple Symbols – this condition is similar to the last except that it calls for two symbols. Here you can put in any symbol and compare some data point regarding that symbol (e.g., 10-minute VWAP, etc.) to the same or a different data point regarding the second symbol. These comparative conditions can apply to different symbols or to the same symbol.   For example, you could specify that you want to buy a certain stock only if it has been in a continuous uptrend. So in addition to the 10-minute VWAP being higher than the 50-day moving average, you would also like the 10-day moving average to be higher than the 30-day moving average on this stock.

1. Products – any product offered by IB (stocks, options, ETFs, bonds, futures, Forex) other than mutual funds;
2. Order Type – market, limit or relative.

IMPORTANT NOTE

This algo will only operate when the trader is logged into the TWS.  If the trader has been logged out prior to the algo completing (either by user action or by the automated nightly restart), a message will appear upon the next log in which will allow for re-activation of the algo.