SMA refers to the Special Memorandum Account, which represents neither equity nor cash, but rather a line of credit created when the market value of securities in a Reg. T margin account increase in value. Its purpose is to preserve the buying power that unrealized gains provide towards subsequent purchases which, absent this handling, could be assured only by withdrawing excess equity and depositing it at the time the subsequent purchase is made. In that sense, SMA helps to maintain a stable account value and minimize unnecessary funding transactions.

While SMA increases as the value of a security goes up, it does not decrease if the security falls in value. SMA will only decrease when securities are purchased or cash withdrawn and the only restriction with respect to its use is that the additional purchases or withdrawals do not bring the account below the maintenance margin requirement. Transactions which serve to increase SMA include cash deposits, interest income or dividends received (on a dollar for dollar basis) or security sales (50% of the net proceeds). It’s important to note that the SMA balance represents an aggregation of each historical bookkeeping entry impacting its level starting from the time the account was opened. Given the length of time and volume of entries this typically encompasses, reconciling the current level of SMA from daily activity statements, while feasible, is impractical. 

To illustrate how SMA operates, assume an account holder deposits $5,000 and purchases $10,000 of securities having a loan value of 50% (or margin requirement equal to 1 – loan value, or 50% as well). The before and after account values would appear as follows:

Next, assume that the long stock increases in value to $12,000. This $2,000 increase in market value would create SMA of $1,000, which provides the account holder the ability to either: 1) buy additional securities valued at $2,000 without depositing up additional funds and assuming a 50% margin rate; or 2) withdraw $1,000 in cash, which may be financed by increasing the debit balance if the account holds no cash. See below:

*EWL represents equity with loan value which, in this example, equals net liquidating equity.

Finally, note that SMA is a Reg. T concept used to evaluate whether securities accounts carried by IB LLC are in compliance with overnight initial margin requirements and it is not used to determine compliance with maintenance margin requirements on either an intraday or overnight basis. It is also not used to determine whether commodities accounts are margin compliant. Similarly, accounts which report negative SMA at the time each day when overnight, or Reg.T initial margin requirements go into effect (15:50 ET) are subject to position liquidations to ensure margin compliance.

Traders should familiarize themselves with the unit of trade convention for BRK B along with IB’s policies with respect to odd lot orders.  Due to the relatively low trading volume in BRK B, NYSE Arca (the primary listing exchange for this security) has designated it as a 10-share unit issue.  A round lot in this security is therefore set at 10 shares as opposed to the standard round lot unit of 100 shares. If your opening buy or sell order is for an amount less than 10 shares, it is considered an odd-lot.  As a matter of policy, odd-lot orders are prohibited from being routed to NYSE Arca.  In addition, only those odd-lot orders which serve to open a position and which are part of a basket order or market-on-close (MOC) order may be sent to NYSE or AMEX.   Opening orders which do not meet that criteria are typically routed to a regional exchange or an ECN where they will remain until a matching order is found.  Odd-lot orders which serve to close a position may be routed to any market center to which IBKR routes orders and can be directed either by the client or via IB SmartRouting.