When an external deficit and public deficit coincide, there must be a private sector deficit, given the sectoral balances framework.
Answer: False
The answer is False.
This question relies on your understanding of the sectoral balances that are derived from the national accounts and must hold by defintion. The statement of sectoral balances doesn't tell us anything about how the economy might get into the situation depicted. Whatever behavioural forces were at play, the sectoral balances all have to sum to zero. Once you understand that, then deduction leads to the correct answer.
To refresh your memory the sectoral balances are derived as follows. The basic income-expenditure model in macroeconomics can be viewed in (at least) two ways: (a) from the perspective of the sources of spending; and (b) from the perspective of the uses of the income produced. Bringing these two perspectives (of the same thing) together generates the sectoral balances.
From the sources perspective we write:
GDP = C + I + G + (X - M)
which says that total national income (GDP) is the sum of total final consumption spending (C), total private investment (I), total government spending (G) and net exports (X - M).
Expression (1) tells us that total income in the economy per period will be exactly equal to total spending from all sources of expenditure.
We also have to acknowledge that financial balances of the sectors are impacted by net government taxes (T) which includes all taxes and transfer and interest payments (the latter are not counted independently in the expenditure Expression (1)).
Further, as noted above the trade account is only one aspect of the financial flows between the domestic economy and the external sector. we have to include net external income flows (FNI).
Adding in the net external income flows (FNI) to Expression (2) for GDP we get the familiar gross national product or gross national income measure (GNP):
(2) GNP = C + I + G + (X - M) + FNI
To render this approach into the sectoral balances form, we subtract total taxes and transfers (T) from both sides of Expression (3) to get:
(3) GNP - T = C + I + G + (X - M) + FNI - T
Now we can collect the terms by arranging them according to the three sectoral balances:
(4) (GNP - C - T) - I = (G - T) + (X - M + FNI)
The the terms in Expression (4) are relatively easy to understand now.
The term (GNP - C - T) represents total income less the amount consumed less the amount paid to government in taxes (taking into account transfers coming the other way). In other words, it represents private domestic saving.
The left-hand side of Equation (4), (GNP - C - T) - I, thus is the overall saving of the private domestic sector, which is distinct from total household saving denoted by the term (GNP - C - T).
In other words, the left-hand side of Equation (4) is the private domestic financial balance and if it is positive then the sector is spending less than its total income and if it is negative the sector is spending more than it total income.
The term (G - T) is the government financial balance and is in deficit if government spending (G) is greater than government tax revenue minus transfers (T), and in surplus if the balance is negative.
Finally, the other right-hand side term (X - M + FNI) is the external financial balance, commonly known as the current account balance (CAD). It is in surplus if positive and deficit if negative.
In English we could say that:
The private financial balance equals the sum of the government financial balance plus the current account balance.
We can re-write Expression (6) in this way to get the sectoral balances equation:
(5) (S - I) = (G - T) + CAB
which is interpreted as meaning that government sector deficits (G - T > 0) and current account surpluses (CAB > 0) generate national income and net financial assets for the private domestic sector.
Conversely, government surpluses (G - T < 0) and current account deficits (CAB < 0) reduce national income and undermine the capacity of the private domestic sector to add financial assets.
Expression (5) can also be written as:
(6) [(S - I) - CAB] = (G - T)
where the term on the left-hand side [(S - I) - CAB] is the non-government sector financial balance and is of equal and opposite sign to the government financial balance.
This is the familiar MMT statement that a government sector deficit (surplus) is equal dollar-for-dollar to the non-government sector surplus (deficit).
The sectoral balances equation says that total private savings (S) minus private investment (I) has to equal the public deficit (spending, G minus taxes, T) plus net exports (exports (X) minus imports (M)) plus net income transfers.
All these relationships (equations) hold as a matter of accounting and not matters of opinion.
To help us answer the specific question posed, we can identify three states all involving public and external deficits:
The following Table shows these three cases expressing the balances as percentages of GDP. You can see that it is only in Case A when the external deficit exceeds the public deficit that the private domestic sector is in deficit.
| Sectoral Balance | Interpretation of Result | Case A | Case B | Case C |
| External Balance (X - M) | Deficit is negative | -2 | -2 | -2 |
| Fiscal Balance (G - T) | Deficit is positive | 1 | 2 | 3 |
| Private Domestic Balance (S - I) | Deficit is negative | -1 | 0 | 1 |
So the answer is False because the coexistence of a fiscal deficit (adding to aggregate demand) and an external deficit (draining aggregate demand) does not have to lead to the private domestic sector being in deficit.
With the external balance set at a 2 per cent of GDP, as the government moves into larger deficit, the private domestic balance approaches balance (Case B). Then once the fiscal deficit is large enough (3 per cent of GDP) to offset the demand-draining external deficit (2 per cent of GDP) the private domestic sector can save overall (Case C).
The fiscal deficits are underpinning spending and allowing income growth to be sufficient to generate savings greater than investment in the private domestic sector but have to be able to offset the demand-draining impacts of the external deficits to provide sufficient income growth for the private domestic sector to save.
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