ABMLP-X Accounting

Balance Sheet

This is a snapshot of the model's economy, showing the assets, liabilities, and net worth (equity) of each sector. The fundamental principle is that for every transaction, there is a "use" of funds (a minus sign, -) and a corresponding "source" of funds (a plus sign, +). For the system as a whole, every transaction must sum to zero, ensuring no money is created or destroyed unaccountably.

How to Read This Table

• Rows: Financial instruments (stocks)
• Columns: Model sectors (agents)
• + (Asset): The sector holds this instrument
• − (Liability / Equity): The sector issues or owes this instrument
• Total column = 0: Ensures full accounting consistency

Balance Sheet

Instrument / Sector	Households	Firms	Private Bank	Fund Manager	Central Bank	Government	Total
1. Reserves (CB)			+A: R		−L: R		0
2. Cash (Physical)	+A: C	+A: C_f			−L: C_total		0
3. Deposits (Bank)	+A: D_h	+A: D_f	−L: D_total	+A: D_fm		+A: D_g	0
4. Household Loans	−L: L_h		+A: L_h				0
5. Firm Loans (Working Capital)		−L: L_f	+A: L_f				0
6. Dividend Loans (Firms)		−L: L_f_div	+A: L_f_div				0
7a. Government Bonds			+A: B_b	+A: B_fm	+A: B_cb	−L: B_total	0
7b. Treasury Bills (T-Bills)			+A: T_b	+A: T_fm	+A: T_cb	−L: T_total	0
8. Equity Shares		−E_all	+A: S_b	+A: S_fm			0
9. Fund Units	+A: U			−L: U			0
Net Worth (Equity)	−E_h	−E_f	−E_b	−E_fm	−E_cb	+E_total	0
Total	0	0	0	0	0	0	0

Key Interpretative Notes

1. Public Sector Consolidation

The Government and Central Bank together form the consolidated public sector. The combined liabilities of this sector - reserves, cash, and government debt - constitute the net financial assets of the non-public sector.

2. Central Bank Holdings of Government Debt

Government bonds and T-bills held by the Central Bank:

• Are assets of the CB
• But represent intra-public-sector claims

These should be consolidated out when analysing private sector wealth.

3. Treasury Bills vs Bonds

The model now distinguishes:

• Bonds → duration-bearing assets
• T-bills → short-term, liquidity-like instruments

This distinction is critical for:

• liquidity dynamics
• reserve pressure
• monetary regime behaviour

4. T-Bills as Near-Money (Zero-Rate Regime)

Under certain conditions (e.g. zero base rate): T-bills can become functionally equivalent to reserves This is operationalised via a Central Bank facility (see Transactions Matrix).

5. Equity Interpretation

• Equity represents net worth balancing items
• Firm equity corresponds to retained earnings / ownership claims
• Bank and CB equity reflects accumulated profit/loss

Transactions Flow Matrix

This matrix shows the flows of the economy - the financial transactions occurring in a single step. These flows update the balance sheet stocks.

How to Read This Table

• Rows: Each row represents a single, distinct type of transaction.
• Columns: Each column represents an agent (or sector) in the model's economy.
• + (Inflow): The agent in this column receives a payment.
• - (Outflow): The agent in this column makes a payment.
• (A, L): An entry in parentheses describes a change to the agent's balance sheet (Assets, Liabilities).
• E: Represents the agent's Net Worth or Equity.
• D / c: Represents a deposit in a current account.
• t: Represents a deposit in a time (savings or custody) account.
• Total column = 0: Ensures full accounting consistency

Transaction	Households	Firms	Private Bank	Fund Manager	Central Bank	Government	Total
1. Government Spending (Firms)		+c	(+A: R, +L: D_f)		+L: R	−G_f	0
2. Government Transfers (Households)	+c		(+A: R, +L: D_h)		+L: R	−G_h	0
3. Household Consumption	−c	+c					0
4. Wage Payment	+c	−c					0
5. Tax Payment (Private Sector)	−c	−c	(−L: D, +L: D_g)	−c	−A: R	+c	0
6. Tax Payment (Bank)			(−A: R, −E)			+R	0
7. Government Debt Issuance (Primary)			(−A: R / −L: D, +A: B/T)		(+A: B/T, +L: R)	−L: B/T	0
8. Bond/T-Bill Sale (Bank → FM)			(−A: B/T, +E)	(+A: B/T, −t)			0
9. Bond/T-Bill Maturity (Private)			(−A: B/T, −L: D_g)	(+t, −A: B/T)		(+L: B/T, −c)	0
10. Bond/T-Bill Maturity (CB)					(−A: B/T, −E)	+L: B/T	0
11. Coupon Payments (Private)			(+A: R, +E)	+t		−BL_g	0
12. Interest on Reserves			(+A: R, +E)		−E		0
13. Loan Creation (Household/Firm)	(+c, −L)	(+c, −L)	(+A: L, +L: D)				0
14. Loan Repayment (Interest)	(−c, −E)	(−c, −E)	(−L: D, +E)				0
15. Loan Repayment (Principal)	(−c, +L)	(−c, +L)	(−A: L, −L: D)				0
16. Fund Investment	(−c, +A: U)		(−L: D_h, +L: D_fm)	(+t, −L: U)			0
17. Fund Fee	−E		(−L: D_fm, +L: D_fm_corp)	(+c, −L: U)			0
18. Cash Withdrawal	(+cash, −c)		(−A: R, −L: D)		(+R, −L: cash)		0
19. Zero-Rate T-Bill Conversion			(−A: T_b, +A: R)		(+A: T_cb, +L: R)		0

Key Flow Interpretations

1. Government Spending

Government spending:

• creates reserves (CB liability)
• creates deposits (bank liability)

This is the primary liquidity injection mechanism.

2. Taxation

Taxation:

• reduces deposits
• drains reserves from the banking system

Tax is a reserve drain, not just an internal transfer.

3. Government Debt Issuance

Debt issuance is:

• a reserve drain
• an asset swap:
  • reserves/deposits → bonds or T-bills

4. Interest on Reserves

Interest on reserves: is paid by the Central Bank

• increases:
  • bank reserves
  • bank equity

This is a core monetary policy transmission channel in the model.

5. Zero-Rate T-Bill Conversion Facility

In a zero-rate, T-bill-only regime:

• banks may exchange T-bills for reserves
• Central Bank balance sheet expands

This mechanism preserves settlement functionality under reserve scarcity.

6. Reserve Cycle Insight

The model naturally generates a liquidity cycle:

1. Government spending → reserves increase
2. Tax + issuance → reserves decrease
3. Conversion / CB actions → reserves stabilised

Much observed market volatility emerges from this mechanical cycle.

7. Timing Note

Currently, within a model step: spending, taxation and debt issuance occur together. Future refinements may separate these temporally to better capture liquidity dynamics.