What is a round lot for Berkshire Hathaway Class B shares?

Overview:

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…

You can create a stock order for a specific dollar amount by adding the "Quantity Value" column to your TWS or by setting up a default Size Amount in your Order Presets.

To add the "Quantity Value" column, click on the configure wrench in the upper right corner of the window window and select "Configure". Click on the "Order Columns" tab and expand the "Quantity" section under "Available Columns. Highlight "Quantity Value" and click the Add button in the middle followed by Apply and OK at the bottom. Once the column is added, simply enter the dollar amount you want to buy or sell. For a buy order, enter the debit amount you want to spend. For a sell order, enter the amount you want to receive as a credit. Based on the current bid/ask, your value gets rounded up or down to the nearest number of shares at the current trading price of the stock. Please note, the minimum order size will always be 1 standard lot (equal to 100 shares) regardless of the amount you enter…

Any size stock order, even if it is not in a round lot increments, can be submitted using a MOO, LOO, MOC or LOC order type. When you SMART route an At-the-Opening or At-the-Close order type, it will be routed to that symbol's primary listing exchange and given to the Specialist. There is never a guarantee that the Specialist will have enough shares available to match all the Buy and Sell orders they receive for an opening or closing cross. Orders are filled on a priority basis with the earliest submitted Market-on-Open orders filled first. If there are any shares still available to cross, the marketable Limit-on-Open orders with the earliest time stamps are next in line. If your order did not get filled, then there were not enough shares available for all of the orders submitted for the Opening or Closing cross trade…

There are a variety of symbol conventions for denoting Berkshire Hathaway Class B shares (CUSIP 084670207).  On the IBKR trading platforms, this security is designated by entering BRK, then a space and then B (BRK B).  This compares to Bloomberg which uses the convention BRK/B and Yahoo Finance which uses BRK-B…