1. (1) Herfindahl-Hirshman Index means the sum of the squares of the market shares of each firm in a relevant market;
2. (2) market share means the percentage of the relevant market controlled by the seller immediately prior to the onset of the abnormal disruption of the market;
3. (3) relevant market means an area of effective competition, comprising both a relevant product market and a relevant geographic market, based on market circumstances immediately prior to the onset of the abnormal disruption of the market;
4. (4) a relevant product market consists of products, including but not limited to essential products, that are reasonably interchangeable with the essential product in the scrutinized sale; and
5. (5) a relevant geographic market consists of the areas where buyers can practically turn for supply of the relevant essential product in the scrutinized sale.
6. (b) Unfair leverage, for purposes of General Business Law § 396-r(3)(a)(ii), includes but is not limited to unfair leverage of market position.

7. (c) A seller that is not a small business will be presumed to have engaged in unfair leverage of market position and thus engaged in an exercise of unfair leverage for purposes of General Business Law § 396-r(3)(a)(ii) if the seller sells an essential product during a disruption and:

   1. (1) the amount the seller charges for the essential product in the scrutinized sale is greater than the pre-disruption price; and

   2. (2) immediately prior to the onset of the abnormal disruption of the market, the seller:

      1. (i) had a market share greater than 30% in a relevant market for that essential product; or
      2. (ii) had a market share greater than 10% in a relevant market for that essential product and the relevant market had a Herfindahl-Hirschman Index of 1,800 or more.

8. (d) A seller may rebut the presumption of subdivision (c) of this rule with evidence that:

   1. (1) as provided in 13 NYCRR § 600.9, the increase in the amount charged in the scrutinized sale preserves the margin of profit that the seller received for the same essential product prior to the abnormal disruption of the market or additional costs not within the control of the seller were imposed on the seller for the essential product in the scrutinized sale; or
   2. (2) specific circumstances in the relevant market demonstrate that, immediately prior to the onset of the abnormal market disruption, the relevant market was not highly concentrated and that the seller lacked market power in the relevant market notwithstanding the seller’s market share or the Herfindahl-Hirschman Index of the relevant market.

(a) Definitions.

In addition to the definitions set forth in 13 NYCRR § 600.1, in this rule: