Central Bank Policy Tools and Monetary Policy Transmission

The central bank (monetary authority) operates its core adjustment of money supply at the base-money injection stage: it influences the excess reserves available to commercial banks through four categories of tools and transmits changes along the re-lending rate (r1) → interbank rate (r2) → loan rate (R) transmission chain into the real economy; in practice this chain becomes “clogged” at regulatory friction points, creating a disconnect between the quantity and price of base-money easing and the financing conditions actually available to the real economy.

The Framework As It Stands

This section is compiled from the compilation research manuscript: the original framework’s structure, terminology, and key formulations are preserved, including editorial bridges and external factual annotations; diagrams are drawn by the compiler following the original structure.

Core Thesis and Hidden Threads

The framework breaks down “how the central bank adjusts money” into two questions: what tools inject/drain base money (volume and price), and how those operations transmit along the interest-rate chain to the real economy. The central bank is technically termed the “monetary authority”; its core task is adjusting the quantity of money more or less [source-transcript 11-22 L5]. Its operational target is not handing money directly to enterprises but rather the base-money injection stage: through re-lending (MLF/SLF, etc.) to inject base money, while simultaneously mandating the required reserve ratio so that banks can create loans and deposits (see The Two-Tier Banking System: T-Accounts and Loans Create Deposits for the foundational mechanism); accordingly the central bank only indirectly controls money [source-transcript 11-22 L17].

Main judgment: the central bank directly controls only two variables — total base-money supply (volume) and the re-lending rate (price, representing the policy stance); everything else (how much banks lend, whether rates transmit downstream) depends on transmission, and transmission in practice gets clogged [source-transcript 11-22 L19 · 11-23 L33].

Three hidden threads:

Hidden Thread A — all tools are adjusting the single pool of “excess reserves”: whether adjusting the required reserve ratio (moving the threshold line between required and excess reserves) or directly injecting/draining base money, the ultimate effect is changing how much excess reserves banks can deploy — this is the true source of market tightness or looseness [source-transcript 11-22 L27, L31, L49].
Hidden Thread B — “injecting liquidity” and “the real economy having cheap money” are two separate things: the ideal transmission chain r1 (re-lending rate) → r2 (interbank/deposit-solicitation rate) → R (loan rate) assumes a highly mature and market-driven system; in practice, regulatory controls on loan allocation, caps on interbank-liability ratios, and similar rules cut the chain, producing a situation where “the central bank has cut rates / injected liquidity, yet loan rates do not fall and the real economy cannot access funding” [source-transcript 11-23 L27, L29, L31].
Hidden Thread C — the money multiplier is a back-calculated result, not a cause: in theory, “base money ÷ required reserve ratio = broad money,” but regulatory requirements and banks’ own buffers prevent full utilization; the actual money multiplier is derived by reverse-calculating from “how much base money was injected and how much broad money was created” — it reflects past creation capacity and cannot be used to predict outcomes [source-transcript 11-22 L61].

Four Categories of Tools

Tool ① · Adjust the required reserve ratio (moving the threshold line between required and excess reserves): raising it → more frozen as required → excess reserves shrink → tightening; lowering it → excess reserves expand → easing [source-transcript 11-22 L31]. Drawback: step size is generally 0.5 percentage points, which at the current scale of the monetary base corresponds to trillions of yuan in funds — far too large a disturbance, making this not a routine adjustment tool [source-transcript 11-22 L33].

Tool ② · Targeted RRR cut: sets specific eligibility conditions, applying the reduction only to qualifying banks, shrinking the impact from roughly ¥1 trillion (universal cut) to ¥200–300 billion — more precise; two functions: reducing the scale of impact + incentivizing banks to engage in specified businesses; because the reserve rate is very low, an RRR cut is favorable to banks (they can redeploy freed-up reserves into government bonds or loans for higher returns), so most banks welcome it [source-transcript 11-22 L37, L39].

Tool ③ · Inject and drain base money: the central bank directly adds or subtracts money in reserve accounts — re-lending / reverse repos / MLF = injection; repayment at maturity = drain [source-transcript 11-22 L49]. Typical scenario: the Chinese New Year cash rush rapidly depletes excess reserves; the central bank responds with liquidity injections (re-lending / reverse repos / MLF) or temporary RRR cuts (temporarily lowering the threshold line, then restoring it after the holiday) [source-transcript 11-22 L43, L45].

Tool ④ · FX reserves + sterilization: FX reserves constitute an uncontrollable base-money injection channel (exporters earn foreign currency → sell to banks → banks sell to the central bank → central bank pays out RMB base money); the central bank responds with “sterilization” — when the uncontrollable channel injects more, correspondingly reduce the controllable channel (re-lending / MLF), keeping total base money at the desired level [source-transcript 11-22 L53, L55].

Money multiplier as back-calculated result: in theory, “base money ÷ required reserve ratio = broad money,” but regulatory requirements plus banks’ own buffers prevent full utilization; the actual multiplier is reverse-derived from “how much base money was injected and how much broad money was created” — it can only look backward at creation capacity, not determine outcomes [source-transcript 11-22 L61].

Ideal Transmission Chain r1 → r2 → R

The basic principle of interest-rate regulation of the economy: loans behave like goods — high rates mean fewer loan applications, low rates mean more; when the economy is weak, rate cuts stimulate lending and economic activity; when the economy overheats, rate hikes slow it down [source-transcript 11-23 L5].

Interest-rate transmission starts from the bank’s balance sheet: re-lending rate r1 → interbank / deposit-solicitation rate r2 → loan rate R; the three funding sources (re-lending / interbank borrowing / soliciting deposits) are substitutes that generally move together, so when the liability-side rate falls, the loan rate also falls (“if the price of flour drops, bread prices generally fall too”), with net interest margin roughly stable [source-transcript 11-23 L13, L23].

Soliciting deposits is essentially transferring base money: deposits are bank liabilities while base money is an asset-side item; when a customer moves a deposit from Bank A to Bank B, the base money moves with it; hence soliciting deposits, interbank borrowing, and borrowing from the central bank via re-lending are all fundamentally means of acquiring base money [source-transcript 11-23 L17].

Transmission Blockages

The framework argues that the transmission mechanism is highly idealized: it requires a high degree of market orientation and mature market development; China has not yet reached this standard, and the United States has not fully reached it either (only more market-oriented); in practice numerous factors break the transmission chain [source-transcript 11-23 L27].

Two typical blockages:

① The central bank cuts rates but regulates loan allocation (“you can’t lend here, you can’t lend there”) → loan supply tightens → loan rate R may not fall (liquidity injected but businesses have no cheap money) [source-transcript 11-23 L29].

② Interbank liabilities must not exceed 1/3 of total liabilities; once a bank hits this ceiling, even if r1/r2 falls it cannot increase interbank liabilities further and must compete for deposits, cutting off the r1 → r2 transmission link [source-transcript 11-23 L31].

Root cause of blockages: banks are a heavily regulated industry; in practice a variety of granular regulatory indicators cause poor interest-rate transmission — this is the clogging of monetary policy transmission under the two-tier banking system [source-transcript 11-23 L33].

Key Data Anchors (course examples, not current data)

Data point	Value	Note
Required reserve ratio step size	0.5 percentage points ≈ trillions of yuan	Too large; not a routine tool [11-22 L33]
Universal RRR-cut scale	~¥1 trillion	Example value, not current data [11-22 L37]
Targeted RRR-cut scale	¥200–300 billion	More precise; ~1/4 of universal cut [11-22 L37]
One-year benchmark rate example	4% (old mechanism example)	Formerly published benchmark rate, not current [11-23 L9]
Interbank liability ceiling	≤ 1/3 of total liabilities	When hit, r1→r2 transmission severed [11-23 L31]

⚠️ The figures above are illustrative / institutional explanations from the recording period (around 2022), not current data; for current policy judgments, use real-time central bank data and annotate separately.

Reasoning-Chain Diagram

flowchart TD
  A["Central bank = monetary authority, directly controls only two variables<br/>Base money quantity (volume) + re-lending rate (price) [11-22 L5,L19]"] --> B["Four tools all adjust the single pool: excess reserves [11-22 L27]"]
  B --> T1["① Adjust required reserve ratio · move threshold line<br/>Up = tight, down = loose · step 0.5% ≈ trillions · not routine [11-22 L31,L33]"]
  B --> T2["② Targeted RRR cut · qualifying banks only<br/>¥1 tn → ¥200–300 bn · favorable to banks [11-22 L37,L39]"]
  B --> T3["③ Inject/drain · re-lending · reverse repo · MLF<br/>Temporary RRR cut to handle CNY cash rush [11-22 L43,L45,L49]"]
  B --> T4["④ FX reserves (uncontrollable) + sterilization<br/>Uncontrollable inflows → reduce controllable channels [11-22 L53,L55]"]
  T1 --> C["Base money → banks create loans and deposits<br/>Money multiplier = back-calculated result, not cause [11-22 L17,L61]"]
  T2 --> C
  T3 --> C
  T4 --> C
  C --> D["Ideal transmission chain r1→r2→R<br/>Three sources as substitutes · stable spread [11-23 L13,L23]"]
  D --> E["Transmission highly idealized · neither China nor US fully achieves it [11-23 L27]"]
  E --> J1["Blockage ①: regulated loan allocation → R does not fall<br/>Liquidity injected but real economy has no cheap money [11-23 L29]"]
  E --> J2["Blockage ②: interbank liabilities ≤ 1/3 cap → r1-to-r2 severed [11-23 L31]"]
  J1 --> K["Root cause: heavy regulation + myriad regulatory ratios<br/>= clogged monetary policy transmission [11-23 L33]"]
  J2 --> K

Compiler’s Perspective

Coordinates: Category · Monetary System and Circulation | axis_h · Fa (Method) | axis_v · Why It Is So

Bridging Layer

What this framework provides is not a tool checklist but a two-step diagnostic procedure for why liquidity injections fail to reach the real economy.

The concrete error of the old way of thinking: upon seeing the central bank announce “a 0.5 percentage point RRR cut” or “MLF injection of X hundred billion,” directly inferring “bank rates will fall, real-economy financing costs will decrease” — this skips the transmission chain and also skips the blockage check. Common misjudgment scenarios: a particular bank’s interbank-liability ratio is already approaching the 1/3 ceiling; after r1 falls, that bank cannot increase interbank liabilities further and can only compete for deposits at high rates, causing actual market rates to rise rather than fall; another scenario: when loan allocation is controlled (restricting specific sectors), even if excess reserves are ample, R does not follow r1/r2 downward. Using the equation “liquidity injection = cheap money for the real economy” leads to the wrong conclusion at exactly these two chokepoints.

Framework-specific analytical assertion: the specific regulatory ratio “interbank liabilities ≤ 1/3 of total liabilities” is the necessary and sufficient checkpoint for determining whether r1 → r2 can transmit — once a bank hits this ceiling, transmission is severed at this link; even if central bank funds are ample and money-market rates fall, that bank is forced to bid aggressively for retail deposits, pushing reported interbank lending rates up rather than down. This check does not appear in macro interest-rate narratives but determines whether transmission holds at the individual-bank level.

Volume-price decoupling: the framework defines “liquidity injection” as a volume operation (injecting base money / cutting the RRR) and defines “whether the real economy has cheap money” as a price outcome (whether R falls); volume easing and price easing are two independent matters, separated by the transmission chain and the blockage check. Analysis should first answer “has volume eased?”, then “where is the blockage in the chain?”, before arriving at a judgment on real-economy financing costs.

Time-point note: the specific figures in the framework (universal RRR cut ~¥1 trillion, targeted cut ¥200–300 billion, benchmark rate 4%, interbank-liability cap of 1/3) are institutional explanations from the recording period; the 1/3 cap was the effective regulatory rule at that time; for current-period judgments, verify the current regulations and latest central bank data.

Sources

Compilation manuscript z-0185 · collected 2026-07
Monetary banking lecture series (collected with identity removed, recorded around 2022); topic: monetary policy tools and the transmission mechanism under the two-tier banking system

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