Stocks and flows

Year-end food-grain stock means the quantity available at a particular date, such as 31 March, so it is a stock. Food-grain production during the year is the quantity produced over an interval of time, so it is a flow. The distinction depends on the measurement period: a date indicates stock, while a duration indicates flow.

Outstanding loans show the total unpaid loan balance existing on a particular date, so they are a stock. New loans issued during a month measure lending activity over a time interval, so they are a flow. A stock is a position at a point in time, whereas a flow records an amount generated, issued, or received during a period.

Output during the year is measured over the whole year, not at one particular instant. It therefore represents a flow. Capital stock at year-end, money supply today, and a bank balance on a date are measured at specified points in time and are stocks. Thus A would be wrongly labelled a stock.

Cash balance held today is measured at a particular point in time, so it is a stock. It represents the amount of cash existing at that moment, not an amount accumulated over a specified period. Monthly income, annual sales, and yearly exports are all measured during periods and are therefore flows. Calling today’s cash balance a flow would be incorrect.

A factory building is a durable fixed asset whose value is measured at a particular date; it is therefore a stock. Annual output is the quantity produced over the course of a year, so it is a flow. The pair in A correctly combines a point-in-time asset with period-based production.

Foreign-exchange reserves are the accumulated foreign assets available at a particular date, so they are a stock. Annual exports are the value of goods and services sold abroad during a year, so they are a flow. The distinction follows from a date-based balance versus activity over a period.

The number of migrants arriving during a year counts an event occurring over a time interval, so it is a flow. The migrant population present on a specified date is a total existing at one point in time, so it is a stock. The wording ‘during the year’ and ‘on a date’ distinguishes them.

A stock is measured at a particular point in time, so ‘on a specific date’ is the most accurate expression. Phrases such as during the year, per month, and throughout a week describe an interval over which an activity occurs; they normally indicate a flow rather than a stock.

A flow is measured over an interval, so ‘during a period’ is the most accurate phrase. Income earned during a month, production during a year, or exports during a quarter are flows. In contrast, on a date, at year-end, and available today refer to point-in-time stocks.

Accumulated debt is the outstanding amount built up and existing up to a particular date, so it is a stock. Annual borrowing is the amount borrowed over the course of a year, so it is a flow. The words accumulated and outstanding usually describe a position at a date, while annual or during the year describes activity over a period.

The bank’s total deposits today represent an accumulated amount measured at one specific point of time, so they are a stock. New deposits received during the month represent an addition measured over a time period, so they are a flow. The same money may contribute to the stock, but the movement during the month is classified as a flow.

Retained earnings reported at the end of the year are an accumulated balance existing at a particular date, so they are a stock. Profit added during the current year is generated over a period and is therefore a flow. The flow of profit can change the stock of retained earnings, but the two terms are not identical.

The change in stock is calculated by the formula: closing stock minus opening stock. Therefore, change in stock = ₹90,000 − ₹1,20,000 = −₹30,000. The negative sign shows that inventories fell during the accounting period. Although the amount of the decrease is ₹30,000, the change itself must be written as negative ₹30,000 because the closing stock is smaller than the opening stock.

Change in stock, also called inventory investment, is calculated as closing stock minus opening stock. Here, the change is ₹2,40,000 − ₹1,75,000 = ₹65,000. Since closing stock is greater than opening stock, inventories have increased. This positive change is included as an addition to investment expenditure in the expenditure method.

GDP is a flow measure, so it records the market value of final goods and services produced within a specified period. In standard national-income accounting, this period is generally one financial or accounting year. A minute, a lifetime, or fifty years is not the normal accounting period used for reporting annual GDP.

GDP is a flow variable because it measures the value of production generated over a period, such as a quarter or an accounting year. A stock is measured at a particular point in time, like wealth or the balance of capital. Since GDP refers to activity during an interval, it is classified as a flow.

A flow variable is measured over a period of time, such as a month, quarter, or financial year. GDP records the value of final goods and services produced during an accounting period, so it is a flow. A stock, by contrast, is measured at a particular point in time, such as wealth on 31 March.

GDP is a flow variable because it records the value of production of final goods and services during a specified period, usually one financial or accounting year. A stock is measured at a particular point in time, such as wealth or capital on a date. GDP therefore cannot be meaningfully stated without mentioning its time period.

GDP is a flow measure: it records the value of final goods and services produced within a country during a specified period, usually one year or one quarter. Focusing on current production prevents previously produced goods and old assets from being counted again when they are resold. A stock measures an amount at a point in time, whereas GDP measures production over time. Therefore, option A is correct.

A flow variable is measured over an interval of time, such as a month, quarter, or year. GDP measures the monetary value of final goods and services produced within a specified period, normally one year. A stock variable, in contrast, is measured at a point in time, such as wealth or inventory on a particular date. Hence, option A is correct.

The governing concept is change in stocks, calculated as closing inventory minus opening inventory. If inventories decline, the closing stock is smaller than the opening stock, so this subtraction produces a negative value. For example, a fall from 100 units to 70 units gives a change of 70 − 100 = −30 units. Thus option D is correct; the change is not always positive, zero or equal to depreciation.

Value of output includes both sales and the change in inventories because goods produced but not yet sold are still part of current production. Therefore, value of output = sales + change in stock = 980 + 65 = 1045 lakh rupees. Option C is correct. Option B ignores unsold output, while A subtracts and D adds an excessive amount.