FINRA Updates Guidance on Fractional Share Trading

FINRA updated guidance on reporting requirements for firms that are engaged in fractional share trading. 

Under the new guidance, firms must populate a new "Fractional Share Quantity" field with the entire trade quantity, including the fractional component up to six digits after the decimal. FINRA stated that firms must continue to populate the existing "Quantity" field with a whole number, rounding up to 1 if the transaction size is less than one share. For transactions smaller than one share where truncating would result in a zero value, firms must report "1" in the sixth decimal place; conversely, for trades larger than one share with minute fractional components, FINRA said firms should report the trade as a whole number and leave the new field blank.

The updated requirements will become effective for NMS stocks on February 23, 2026. FINRA clarified that firms not engaging in fractional share trading are not required to make system changes, as the new field must remain blank for whole-share trades. While the update applies to NMS stocks reported to TRFs or the ADF, FINRA noted that the implementation date for OTC Equity Securities will be announced in a future notice.