Inventory Management

Topics

Meaning of inventory management Types of inventories Need for inventory Cost of holding inventories Characteristics of inventory situations Selective inventory control Inventory Control Models Control devices Inventory management & valuation

MEANING OF INVENTORYMANAGEMENT

Inventory management is concerned with keeping enough product on hand to avoid running out while at the same time maintaining a small enough inventory balance to allow for a reasonable return on investment. Excessive level of inventory, results in large inventory carrying cost.

An efficient system of inventory management will determine(a) what to purchase(b)how much to purchase(c)from where to purchase(d) where to store

Objects of inventory Mgmt.

TO ENSURE CONTINUOUS SUPPLY OF RAW MATERIAL, SPARES AND FINISHED GOODS.TO AVOID BOTH OVERSTOCKING AND UNDERSTOCKING OF INVENTRY.TO MAINTAIN INVESTMENTS IN INVENTRIES AT OPTIMUM LEVEL.TO KEEP MATERIAL COSTUNDER CONTROL.

TO ELIMINATE DUPLICATION IN ORDERING OR REPLENISHING STOCKS.TO MINIMIZE LOSSES THROUGH WASTAGE AND DAMAGES .TO FACILITATES FINISHING OF DATA.

TYPES OF INVENTORIES

(a) RAW MATERIAL:

A inventory of raw materials allows separation of production scheduling from arrival of basic inputs to the production process.

(b) WORK-IN-PROGRESS: An inventory of partially completed units allows the

separation of different phases of the production process.

(c) FINISHED GOODS:

An inventory of finished goods allows separation of production from selling.

(d) CASH & MARKETABLE SECURITIES:

Cash & marketable securities can be thought of as an inventory of liquidity that allows separation of collection from disbursement.

Need for Inventories

Transaction motive: The transaction motive for holding inventory is to satisfy the expected

level of activities of the firm.

Precautionary motive: The precautionary motive is to provide a cushion in case the actual

level of activity is different than anticipated. Speculative motive: The speculative motive is to purchase larger quantity of

materials than normal in anticipation of making abnormal profits.

COST OF INVENTORIES

The determination of inventory cost is essentially an income measurement problem. Relevant inventory costs which change with the level of inventory are listed below:

a) Ordering cost: Every time an order is placed for stock replenishment, certain cost are involved. This cost of ordering includes:

- Paper work costs, typing & dispatching. - order inspection cost, checking & handling.

b) Carrying costs or cost of holding inventories Carrying costs constitute all the cost of holding items in inventory for a given period of time. This cost involves:

Capital Cost -Storage & handling costs. -obsolescence & deterioration costs. -Insurance. -Taxes. -The cost of funds invested in inventory.

c) Stock out costs:

Stock out costs are incurred whenever a business is unable to fill orders because the demand for an item is greater than the amount currently available in inventory. This cost involves:

-Expenses of placing special orders. -Expediting income orders. -Cost of production delays.

CHARACTERISTICS OF INVENTORY SITUATIONS

1) Lead time: Obtaining inventory usually requires a time lag from

the initiation of the process until the inventory starts to arrive. This lead times may be few min.or months.

2) Sources & level of risk: Where there are substantial uncertainties & where

the costs of stockout are important . Strategies for addressing risk must be formulated.

3) Static versus dynamic problems: In static inventory problems, the goods

have a one-period life; there can be no carryover of goods from one period to next.

In dynamic inventory problems, the goods have value beyond the initial period; they do not lose their value completely overtime.

Selective Inventory Control

I. Explosion process: In many manufacturing organization, production requirements

are based directly on the sales forecast. For each of its products, the company prepares a bill of material needed for various products.

II. Past-usage methods: The other method used for determining the production

requirements relies on the past usage, rather than on the sales forecast . If a certain item was used at the rate of 100 units per month during the past year or during some other period is likely to be used at the same rate in future.

III. Value-volume Analysis: This analysis is used to determine which

inventory accounts should be controlled by the explosion method & which should be controlled by past usage method. In value-volume analysis the no. of each item used in the past year is multiplied by its unit to find the annual activity for the item.

IV. A-B-C ANALYSIS: The materials are divided into three categories viz, A ,B &C CATEGORY-A: Under this almost 10% of the items contribute to 70% of

value of consumption. CATEGORY-B: Under this category 20% of the items contribute about 20%

of value of consumption. CATEGORY-C: Under this category about 70% of items of material contribute

only 10% of value of consumption.

V. HML Classification: The HML (high, medium, low) classification is similar to ABC

classification, but in this case instead of the assumption value of the item, the unit value of the item is considered.

VI. XYZ Classification: The XYZ classification has the value of inventory stored as

the basis of differentiation. X items are those whose inventory value are high while Z

items are those whose value are low.

VII. VED ANALYSIS: The VED analysis is used generally for spare parts. The requirements and urgency of spare

parts is different from that of materials. spare parts are classified as vital (V), essential (E) ,desirable (D).

VITAL SPARE PARTS: These are must for running the concern smoothly.

ESSENTIAL SPARE PARTS: Necessary but stock kept at low figures.

DESIRABLE SPARE PARTS: May be avoided at times

VIII. FSN Analysis: Movement analysis forms the basis for FSN (fast moving,

slow moving, non-moving) classification & the items are classified according to their assumption pattern.

IX. SDF & GOLF Analysis:

The SDF (scarce, difficult, easy to obtain) classification & the GOLF (government, ordinary, local, foreign sources) are the systems where analysis is done on the basis of general availability & the source of suppliers.

INVENTORY CONTROL MODELS

1) EOQ MODELS: Economic order quantity is the

size of the lot to be purchased which is economically viable.

EOQ IS MADE UP OF TWO PARTS

ordering costs: requisitioning, order placing, transportation, receiving, inspecting and storing, administration

– carrying costs: warehousing, handling, clerical and staff, insurance, depreciation and obsolescence

– ordering and carrying costs trade-off:

2EOQ =

AO

c

2. Just-In- Time Inventory Management System:

A key part of just-in-time techniques is the replacement of production in large batches with a continous flow of smaller quantities. It is based on the idea that all required inventory items should be supplied to the production process at exactly the right time & in right quantity.

CONTROL DEVICES

i) Control Account: The control is maintained in the general ledger by

accounting. All material purchases are charged against the account & all issuances are credited to it.

ii) Physical Counting: Physical counting of stock on hand for tax & cost

accounting functions & as a means of verifying the balance showed on perpetual inventory records & in the control account.

iii) Visual Review: A highly subjective method of determining when to reorder is

a visual reviews of stock in inventory. For ex: in the old time general store, the owner would inspect his inventory & determine what should be ordered.

iv) Two-bin system: The two-bin system divides each item of inventory into two

groups. In first, sufficient supply is kept to meet current demand, In second, additional items are available to meet the demand during load time.

v) Minimum- maximum system:

The minimum-maximum system is frequently used in connection with mannual inventory control systems. The min quantity is established in the same way as any reorder point.

vi) Periodic order system: Under this system, the stock levels for all inventory accounts

are reviewed at established intervals, & orders are placed to bring all accounts up to their max level.

INVENTORY MANAGEMENT & VALUATION

A) Average cost method:

For determining the valuation of inventories, consistency from year to year is of prime importance & for this average cost method is appropriate. In this method, weighted average prices are taken with price of each type of material in stock are taken together.

B) First-in-First-out Method:

Under FIFO method, Items received first are assumed to be used first & therefore prices charged are those paid for early purchase. care has to be taken to ensure that each quantity is issued at the correct price.

C) Base Stock Method:

Under this method, the base quantity is carried forward at the cost of the original stock. If a quantity of goods larger than the base stock is owned at the end of any period, the excess will be carried at its identified cost or at the cost determined under FIFO method.

D) Last-In, First-Out Method:

Under LIFO it is assumed that the stock sold or consumed in any period are those most recently acquired or made. The result at the LIFO method is to charge current revenues with amount approximating current replacement cost.