La. Revenue and Taxation § 47:1961
In the assessment of merchandise or stock in trade on hand, the inventory value of the merchandise shall be ascertained by computing the cost or purchase price at the point of origin, plus the carrying charges to the point of destination, and the average value as so determined during the year preceding the calendar year in which the assessment is made shall be the basis for fixing the assessed value.
All persons engaged in manufacturing or in the business of retailing or wholesaling merchandise in the state, whose gross sales are in excess of fifteen thousand dollars ($15,000.00), shall make and keep an inventory of their merchandise, fixtures, machinery, equipment, and other assets within the state showing the quantity, description, and value thereof as of the first day of January of each year; such persons shall likewise make and keep on hand a true and accurate record of all purchases and sales of merchandise made, and a true and accurate record of all other business transactions had in connection with their stores, mercantile or manufacturing establishments.
These inventories and records shall be separately made for and kept on hand in each store or establishment within the state, and shall be open for inspection by the tax assessor or any of his deputies, or any other taxing authority, at any reasonable time; when demanded by one of the officers at such time, the inventories and records shall be produced and the officers afforded the opportunity to make a complete and thorough examination of the inventory and records for the purpose of ascertaining the proper assessment to be made of the property of such person. The inventories and records for more than one establishment belonging to the same person may be kept for inspection at one place of business within the state, but in this event such records shall be open for inspection to the assessors and their deputies, or any other taxing authorities of the entire state, and shall be made in such manner as to segregate the stores or establishments from each other and from those in other parishes, and information as to the place where such inventories and records are kept shall be given the tax assessors and deputies and other taxing authorities, on demand. The inventories and records shall be kept on hand for a period of three years from the thirty-first of December of the year for which they were made or kept. Failure to comply with the provisions of this section, shall estop the person so failing, from contesting the amount of the assessment placed by the assessor, or other taxing authority upon his or its property.
La. Revenue and Taxation § 47:1961