Exchange Tweaks Rules to Match New Round-Lot Standard
Published Date: 6/3/2026
Notice
Summary
Green Impact Exchange (GIX) is updating two of its rules to match a new official definition of a 'round lot'—basically, the standard number of shares in a stock trade. This change affects traders and brokers using GIX and takes effect immediately, keeping everything smooth and clear. No extra costs or delays are expected, just a neat alignment with the latest market rules.
Analyzed Economic Effects
4 provisions identified: 4 benefits, 0 costs, 0 mixed.
GIX Adopts Reg NMS Round Lot Rule
If you trade or clear trades on Green Impact Exchange (GIX), the Exchange replaced its 100-share ‘Round Lot’ definition with a reference to the Round Lot sizes set by Rule 600 of Regulation NMS. This change became operative when GIX filed the rule change on May 26, 2026 and is intended to align GIX rules with the national Rule 600 definition without added costs or delays.
Official Round Lot Sizes and Schedule
Rule 600 of Regulation NMS now defines Round Lots for NMS stocks by average closing price: 100 shares for $250.00 or less; 40 shares for $250.01–$1,000.00; 10 shares for $1,000.01–$10,000.00; and 1 share for $10,000.01 or more. Adjustments to the Round Lot occur semiannually using a one-month Evaluation Period (March for May assignments, September for November assignments); the revised definition was implemented beginning November 3, 2025.
Immediate Operation and Comment Period
The Commission waived the usual 30-day operative delay so GIX's rule amendments became operative upon filing on May 26, 2026. Interested persons may submit comments on file number SR-GIX-2026-01 on or before June 24, 2026.
GIX Quote & Trading Unit Text Aligned
GIX amended its 'normal unit of trading' and Two-Sided Quote Obligation language (Exchange Rules 14.003(a)(30) and 11.151(a)(1)) so they refer to the Round Lot as defined in Exchange Rule 11.180, which in turn references Rule 600 of Regulation NMS. The change is presented by the Exchange as conforming and non‑substantive.
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