47 CFR 52.109: Permanent cap on number reservations.

(a) A Responsible Organization may have in reserve status, at any one time, either 2000 toll free numbers or 7.5 percent of that Responsible Organization's numbers in working status, whichever is greater.

(b) A Responsible Organization shall never reserve more than 3 percent of the quantity of toll free numbers in spare status as of the previous Sunday at 12:01 a.m. Eastern Time.

(c) The Wireline Competition Bureau shall modify the quantity of numbers a Responsible Organization may have in reserve status or the percentage of numbers in the spare pool that a Responsible Organization may reserve when exigent circumstances make such action necessary. The Wireline Competition Bureau shall establish, modify, and monitor toll free number conservation plans when exigent circumstances necessitate such action.