Round Lots Regulatory Changes
The Securities and Exchange Commission (SEC) has adopted a new definition of "round lot" to improve the transparency of stock quotes and orders for investors and other market participants. This new definition, and other new regulations, will impact how bid, ask, and last sizes appear across all Schwab platforms, including Schwab.com and thinkorswim®.
No action is required from investors or traders. Schwab will automatically implement the new display across all platforms on November 3, 2025.
For additional details, refer to the SEC Final Rule for Regulation National Market System: Minimum Pricing Increments, Access Fees, and Transparency of Better Priced Orders.
Changes to round lot sizes
A round lot is the standard trading unit for securities. Exchanges and brokers have historically displayed bid, ask, and last sizes based on the number of round lots available, but that will now change.
Beginning November 3, 2025, bid, ask, and last sizes for stocks listed on a national exchange will display in terms of the number of actual shares, rounded down to the nearest multiple of a stock's round lot size.
Stocks' average closing prices will determine their round lot size, which will be as follows:
These assigned round lot sizes will be updated semiannually, with a new round lot size beginning on the first business day in May and November each year.
Display changes
Due to these new regulations, bid, ask, and last sizes will display differently on Schwab platforms depending on the level of trading data available.
For reference, Level 1 trading data shows basic pricing information, while Level 2 data offers more in-depth pricing information, including the complete order book.
For Level 1 data, bid, ask, and last size quotations will be listed in terms of the number of shares, rounded down to the nearest multiple of the round lot size assigned to the security. Previously, quotation sizes represented the number of round lots available at the quoted price.
For example, here's how a bid size of 251 shares will be displayed after November 3 in Level 1 data, based on a stock's price:
- For a stock trading below $250, the 251-share bid size will display as 200 shares because 200 shares is the nearest multiple of 100 shares when rounding down.
- For a stock trading between $250.01 and $1,000, the 251-share bid size will display as 240 shares because 240 shares is the nearest multiple of 40 shares when rounding down.
- For a stock trading between $1,000.01 and $10,000, the 251-share bid size will display as 250 shares because 250 shares is the nearest multiple of 10 shares when rounding down.
- And for a stock trading above $10,000.01, the 251-share bid size will display as 251 shares because 251 shares is the nearest multiple of one share.
Level 2 quotation data will display the actual share amount, and intraday charts will only reflect trades that meet the new round lot criteria. Visit the thinkorswim learning center for more information on the display update for Level 2 data.
Examples of display changes
Below are examples of how bid, ask, and last sizes will appear in different situations on Schwab.com starting November 3.
This first example shows the Schwab Stock Slices™ order review screen. The bid and ask sizes appear as 200 shares and 400 shares for Netflix (NFLX). Because Netflix is currently trading above $1,000, its round lot size is 10 shares. These figures represent the number of shares available, rounded down to the nearest multiple of 10. Previously, these values would have displayed as 2 and 4, indicating the number of round lots available, rather than the total share count.
Now let's look at an example using the Positions subtab. The bid, ask, and last sizes display differently for each stock based on that stock's assigned round lot size. For Nike (NKE), which is trading below $250, these quotations display as multiples of 100 shares, reflecting its assigned round lot size. For McDonald's (MCD), which is trading between $250.01 and $1,000, the quotations show as multiples of 40 shares, reflecting its assigned round lot size.
As a reminder, Schwab clients do not need to take any action. These display changes will take effect automatically on November 3, 2025, across all Schwab platforms. Please reach out to Schwab customer service at 1-877-519-1403 with any questions or concerns.
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