# Block 023 — FX CIP / UIP

**Status:** ● covered
**Phase:** Phase 1 (FX)

## Topic scope

Covered Interest Parity (CIP) and Uncovered Interest Parity (UIP). CIP basis mechanics: borrow in A, convert to B, lend B, lock forward = A rate - B rate. CIP deviations and what they signal (USD funding stress, quarter-ends). UIP empirical failure.

## Plan

**Prerequisite:** Block 00a (rubric), Block 00b (anti-patterns). FX basis trades have specific margin requirements. Block 014 (cross-currency basis) — covered the diagnostic-framework substrate that Block 023 builds on.

**Status:** ● covered (Session 31, 2026-07-23 — pre-block probes 1-4 + Target 1 CIP mechanics main material landed at Working+; Session 32, 2026-07-26 — Targets 2-4 fully landed: Target 2 CIP deviations, Target 3 UIP failure, Target 4 basis diagnostic + Block 014 three-signal-layer tie-in. All at Working+.)

**Pre-reads (assigned 2026-07-21, Session 30 close — Block 022 close):**

**Source 1: Kenen (1985) — *The International Economy*, Ch. 1-4.** CIP as the no-arbitrage cornerstone: direct USD rate = synthetic USD rate (deposit foreign + convert via forward). UIP as the risk-neutral extension: expected depreciation = interest differential. The CIP→UIP link under risk neutrality.

**Source 2: Du, Tepper, Verdelhan (2017) — NBER WP 23170.** Four facts of post-GFC CIP deviations: (1) large, persistent, systematic (24bp avg at 3M, 27bp at 5Y for G10 2010-2016); (2) largest at quarter-ends — the balance-sheet regulation signature (SLR, leverage ratio, G-SIB); (3) correlates with other fixed-income liquidity spreads; (4) NOT explained by credit risk (survives repo and KfW bond controls). The puzzle: these look like arbitrage opportunities, but the binding constraint is intermediary capital, not arbitrageur logic.

**Source 3: BIS Triennial 2025 (with 2022 and 2019 comparators).** Global FX turnover $9.6T/day in April 2025 (+28% from $7.5T in 2022, +45% from $6.6T in 2019). FX swap $4.0T/day — still the single largest instrument, but share dropped to 42% in 2025 (from 51% in 2022) as spot, outright forwards, and FX options grew faster. USD on 89.2% of trades (up from 88.4% in 2022, ~88% in 2019 — structurally stable). Scale matters: a 24bp basis on a $100B Japanese pension hedging USD assets is $240M/year of real-money transfer to dealer balance sheets — and the basis is now the 2025 figure (still 24bp range), but the underlying FX swap market is ~5% larger than 2022, so the absolute hedge volume and dealer balance-sheet load has grown commensurately.

**Synthesis:** CIP deviations are a diagnostic of dollar funding stress + balance-sheet constraint tightness, not an arbitrage price. Basis level + sign + velocity + cross-section reads the regime: quarter-end spike = technical (regulatory balance-sheet), persistent negative = structural hedging demand exceeding dealer capacity, sudden blowout = acute dollar shortage (2008, March 2020), cross-currency spread = which currency's hedging demand is dominant.

**Skip:**
- Full Du-Tepper-Verdelhan (2017) econometric derivations — use the framework
- Full BIS Triennial 2022 paper — only the FX swap section
- Detailed FX option vol mechanics (Block 029 territory)
- Specific historical FX crisis accounts (covered in Block 026)

**Total: ~60 min, [thematic] as assigned.**

**Pre-block intuition probes (added 2026-07-21, Session 30 close — rephrased from fact-recall to causal-mechanism per user pushback, not tested until Session 31 open):**

1. **USD/JPY basis blowout regime read.** "You see USD/JPY cross-currency basis blow out to -100bp at end-March 2020 versus the same basis trading at -25bp on a normal 2019 quarter-end. The qualitative difference — what is it telling you about the dollar funding market, and what changes in your positioning?"

2. **Persistent negative basis as a structural read.** "USD/JPY basis has traded persistently in the -20 to -30bp range for years post-GFC, with no quarter-end spike pattern. That is NOT the same diagnostic as the March 2020 episode. What is the basis telling you here, and what does the absence of a quarter-end pattern imply?"

3. **Cross-currency basis spread.** "USD/JPY basis is at -25bp while USD/EUR basis is at -8bp. Why is there a cross-currency spread, and what does the relative magnitude tell you about hedging demand in each currency?"

4. **Block 014 carry-forward — term structure of the basis.** "DTV 2018 finds the basis is largest at short tenors and shrinks toward zero at 5y. What is the intuitive reason for that term-structure shape, and what does it tell you about where in the dealer balance-sheet the constraint binds?"

5. **Block 014 carry-forward — three-signal-layer diagnostic.** "If SOFR-OIS blows out AND cross-currency basis blows out AND MBS-Treasury basis blows out simultaneously, versus just the cross-currency basis moving alone, what does each scenario tell you about which layer of dollar funding plumbing broke?"

**Main material — load-bearing targets:**
1. CIP mechanics: borrow in A → convert to B → lend B → lock forward = A rate − B rate. The identity, the cash-and-carry equivalence.
2. CIP deviations: when and why they open. The "balance-sheet cost" mechanism (SLR / leverage ratio / dealer balance-sheet constraints). The 2008 GFC + March 2020 case anchors.
3. UIP empirical failure: the carry trade puzzle. Why high-yielders tend to *appreciate* (not depreciate as UIP predicts).
4. Diagnostic: what does the basis level + sign + velocity tell you about USD funding stress?

**Cold-recall re-drill queue (carried from Block 014):** DTV 2018 CIP finding (basis largest at short tenors, shrinks toward zero at 5y) + the three-signal-layer diagnostic (which combination of legs moves = which layer of dollar-funding plumbing broke). All at Working, re-verify at Session 31 open.

**Live-data exercise at block close:** pull current 3M USD/JPY cross-currency basis and 3M EUR/USD basis; classify regime (normal / quarter-end stress / funding stress); articulate the diagnostic in terms of the three signal layers. Compare to Cbonds FX swap points (per Block 014 surgical correction — different series, different scale).

## Session history

### 2026-07-23 — Session 31 (Block 023 partial — pre-block probes + Target 1 main material)

**Status:** ○ queued → ● partial (pre-block probes 1-4 complete at Working+; Target 1 CIP mechanics main material landed; Targets 2-4 deferred. Session paused mid-Block per user request.)

**Pre-block probes (4/4 complete, all Working+ after refinements):**

- **Probe 1 (March 2020 blowout diagnostic):** user correctly identified the qualitative difference between -25bp quarter-end and -100bp blowout, and the diagnostic instinct to check SOFR-OIS + MBS-Treasury legs. **Direction-of-trade correction needed:** user framed the basis as "increased carry" to put on a new carry trade — inverted. Negative basis is *cost* to USD-funded carry traders, not free carry. The -100bp blowout is a *short-dollar* / *reduce-dollar-exposure* signal, not a long-dollar carry-entry signal. Working+ after correction.
- **Probe 2 (persistent -25bp structural read):** correctly identified the absence of quarter-end pattern as "banks at the edge of what's worthwhile." **Refinement:** persistent negative basis IS a signal (structural dollar scarcity, not "no signal"), and the absence of quarter-end pattern reflects the post-GFC regulatory regime binding balance sheet 24/7, not just at reporting dates. Working+ after refinement.
- **Probe 3 (cross-currency spread JPY -25bp vs EUR -8bp):** correctly identified JPY as the dominant structural carry-trade funding currency (BOJ ZIRP duration, GPIF/pension USD hedging demand). Mechanism clear, magnitude story right, direction-of-hedging framing (sell USD forward = basis is cost to hedgers) locked. Working+.
- **Probe 4 (term structure, short-end widest):** correctly identified the short-end as where the constraint binds. **Mechanism refinement:** velocity = dealer balance-sheet *turnover*, not price volatility. The constraint binds where the dealer has to roll the position most frequently (short tenor, high frequency), not where price moves most. Working+ after refinement.

**Target 1 / 4 main material (CIP mechanics — intuition, not formula):**

- No-arbitrage frame: bank should not be able to borrow cheap currency, convert, lend rich currency, lock forward, and earn free money. Forward rate = interest rate differential exactly (CIP says so). When basis breaks, someone absorbs a cost.
- Hedger A/L framing: Japanese pension fund holds $1B UST, wants to eliminate FX risk (JPY liabilities). Sell USD/JPY forward = lock in future JPY amount. *Fair* hedge cost = US Treasury yield − JPY funding rate. Negative basis = hedge costs 25bp *more* than fair value. The premium is dealer compensation for SLR/leverage-ratio balance-sheet cost, not arbitrageur capture.
- BOJ exit mechanism (sub-probe): rising JPY rates don't directly move the basis in steady state (existing positions sticky; hedgers don't immediately change behavior). Second-order: higher JPY rates → JPY assets more attractive → JPY institutions reduce USD asset allocation → less hedging demand → less structural short-dollar demand → basis *compresses* (not expands). **Initial slip corrected:** user said rising JPY rates → basis expands (carry unwinds). Correct: basis compresses via the demand-side mechanism, not the carry-trade side (carry trade is unhedged USD positioning; basis is hedged USD positioning — different populations).
- BOJ unexpected rate shock mechanism (sub-probe): vol spike → dealer market-making capacity stretched → short-tenor basis blows out first (velocity signature) → term structure steepens. Mechanism substrate firing cleanly.

**Status transitions:**

- FX — CIP negative basis = balance-sheet cost to dealers, not arbitrageur capture: Untested → **Working+** (intuition frame, no-arbitrage rationale, hedger-dealer mechanism)
- FX — Post-GFC structural basis = constraint binds always, not just quarter-end: Untested → **Working+** (mechanism + diagnostic frame)
- FX — Cross-currency basis spread = relative carry-trade scale + regulatory backstop: Untested → **Working+**
- FX — Term structure short-end widest = dealer balance-sheet turnover velocity, not price volatility: Untested → **Working+** (after velocity = turnover refinement)
- FX — BOJ exit second-order on basis = demand-side compression via asset-allocation shift: Untested → **Working** (sub-probe landed; full Working+ after Targets 2-4 reinforce)

**Coverage tracker:** Block 023 → `partial` (pre-block probes + Target 1 landed; Targets 2-4 deferred).

**Carry-forwards to next session:**

1. **Open diagnostic probe re-attempt** (paused mid-Session 31): USD/JPY basis -22→-45bp with cross-section break (EUR -9bp) + term-structure distortion (JPY 1m -60bp, 5y -15bp). Three signatures. Needs Target 2 substrate anchoring first before re-pose.
2. **Target 2 (CIP deviations) substrate** — when and why they open. Three signatures: acceleration, cross-section break, term-structure distortion. 2008 + March 2020 anchors.
3. **Target 3 (UIP empirical failure)** — the carry trade puzzle, deferred.
4. **Target 4 (basis diagnostic)** — level + sign + velocity tells you about USD funding stress, deferred.
5. **Block 014 cold-recall re-drill queue** — three-signal-layer diagnostic (MBS-Treasury / SOFR-OIS / cross-currency basis). To be exercised during Target 4.

**Pre-reads for next session:** None new. Block 023 pre-reads (Kenen Ch. 1-4 + DTV 2017 + BIS Triennial 2022 FX swap section) already complete per user confirmation at Session 31 open. The pre-reads are substrate-loaded for the remaining Targets 2-4.

**Process changes filed this session:**

- **2026-07-23 — Probe form: open diagnostic probes need stronger anchoring (Session 31, Block 023 mid-pause):** the open diagnostic probe (USD/JPY -22→-45bp with cross-section break to EUR -9bp + term-structure distortion JPY 1m -60bp / 5y -15bp) was the natural Target 2 transition probe, but the substrate anchoring was implicit (relied on Probes 1-4 working substrate as the base). When the session paused, the cleanest restart point was to re-anchor Target 2 substrate first (when/why CIP opens, the three signatures) THEN re-pose the diagnostic probe. **Going-forward rule:** open diagnostic probes that aggregate prior probes' substrate should be preceded by a 2-3 sentence re-anchor of the substrate the probe is aggregating. Same logic as the verify-before-recall-on-live-data-probes rule.

**Pointer:** `_meta/current-block.md` updated. Block 023 → partial. Block 023 resumes next session with Target 2 substrate + re-posed diagnostic probe. `pre-reads.md` unchanged (Block 023 pre-reads remain valid; no new pre-reads needed for resume).

### 2026-07-26 — Session 32 (Block 023 — Target 2 forward + Target 3 + Target 4 — COMPLETE)

**Status:** ● partial → ● covered (Block 023 fully closed).

**Pre-reads:** accepted on user word per Session 26 convention. Block 023 pre-reads (Kenen Ch. 1-4 + DTV 2017 + BIS Triennial 2022 FX swap section) confirmed done; valid for Targets 2-4.

**Diagnostic probe re-posed (per Session 31 process rule):** USD/JPY 3m basis -22→-45bp (one week), USD/EUR 3m basis -9bp (unchanged), JPY term structure 1m -60bp, 5y -15bp. Substrate re-anchored (three signatures of CIP opening) before the probe. User correctly identified: (1) acceleration = acute JPY-specific dollar scarcity, (2) cross-section break = JPY-specific not global, (3) term-structure shape = balance-sheet/velocity regime (NOT inverted — user caught the framing error). **Combined read: JPY-specific acute balance-sheet tightening.**

**Inverted-curve follow-up question (user-driven):** user correctly flagged that the term-structure shape was not inverted (5y -15bp is *higher* than 1m -60bp, not lower — the long end is closer to zero). Diagnostic sharpened: the shape is "normal short-end binding at uniform stressed levels" = balance-sheet regime. An inverted curve (5y wider than 1m) would signal price-driven regime instead. Substrate distinction locked.

**Target 2 (CIP deviations) main material — three signatures + two anchor cases:**

- **Three signatures of CIP opening:** acceleration (velocity, days not weeks), cross-section break (currency-specific vs systemic), term-structure distortion (balance-sheet vs price-driven). The *combination* of these tells you the type of shift.
- **2008 GFC anchor:** all cross-currency bases blew out (cross-section absent — systemic), term structure inverted at peak, acceleration acute. Mechanism: dealer balance-sheet collapse + foreign real-money flight-to-USD. Fed response: dollar swap lines.
- **March 2020 anchor:** partial cross-section break (JPY + EUR + EM), extreme term-structure distortion (1m -100bp+, 5y near normal), dash-for-cash dynamic. Fed response: swap lines + standing repo + unlimited QE.
- **Diagnostic insight:** order of Fed facility activation = which layer of plumbing broke first.

**Target 3 (UIP empirical failure) main material — the carry trade puzzle:**

- UIP predicts USD with higher rate should depreciate; empirical failure: high-yield currencies tend to *appreciate*.
- Three competing explanations: risk premium for crash risk, peso problem, behavioral / order-flow.
- **Carry-trade vs hedged-investor population distinction (load-bearing substrate):** Carry trader (unhedged) = long USD asset, short JPY funding, no FX hedge, P&L = USD bond yield + FX delta. Hedged USD investor = long USD asset + short USD/JPY forward hedge, P&L = USD bond yield − basis (the hedge cost). **The carry trader does NOT trade the basis.** The basis is paid by the hedged investor. Carry trade unwind does NOT directly move the basis (it's a Treasury market move + side-effect basis blowout via vol spike + dealer capacity contraction + general dollar strength).
- User initially conflated the two populations on a Fed-hike unwind scenario; re-anchored the population distinction explicitly. Substrate landed after second teach.
- **Diagnostic:** carry trade unwind + basis blowout together = systemic; divergence = normal regime.

**Target 4 (basis diagnostic + Block 014 tie-in) main material:**

- The basis is a single-number summary; to read it you need level + sign + velocity + cross-section + term structure.
- **Three-signal-layer diagnostic (Block 014 carry-forward):** SOFR-term-vs-OIS (domestic bank funding) + cross-currency basis (global dollar funding) + MBS-Treasury (mortgage market). Combinations identify which layer of plumbing broke.
- **Reframed 2026-07-26 (Session 32 retro):** The Fed is a participant with constraints, not a diagnostic. Three reasons: (1) **Diagnostic lag** — the Fed identifies the problem after the market has priced it (basis moves first, Fed responds). (2) **Tool-selection noise** — the Fed picks what it can do under its own constraints (legal authority, balance-sheet capacity, political cover, FOMC consensus), not just what's optimal for the problem. (3) **Cross-objective friction** — multiple objectives (price stability, employment, financial stability, fiscal-cost management) mean the tool choice is a negotiation, not a discovery. **The PM edge is the gap between the market's leading read and the Fed's trailing response.** Position *before* the Fed acts, not after. The basis is the entry trigger; the Fed's tool choice is the confirmation.

**Cold-recall close probe (March 2020 scenario):** USD/JPY 3m -100bp + SOFR-OIS +30bp + MBS-Treasury -50bp + DXY +5% + EM FX -5-10%. User correctly identified: (1) systemic global dollar funding crisis, (2) position expressed as bet on Fed response (long basis = bet compresses), (3) facility activation order: cross-currency basis broke first March 9 → swap lines activated March 15 → standing repo + QE followed.

**Anki cards generated (Session 32):** 10 atomic Basic cards pushed via AnkiConnect + synced + verified. Note IDs: 1785099068969, 1785099068994, 1785099069023, 1785099069044, 1785099069067, 1785099069095, 1785099069116, 1785099069144, 1785099069166, 1785099069195. Cards: (1) two populations + P&L, (2) carry trader doesn't trade basis, (3) basis existing vs new hedge positions, (4) systemic vs normal diagnostic, (5) term-structure shape diagnostic, (6) three signatures of CIP opening, (7) UIP failure mechanism, (8) basis diagnostic vs tradeable, (9) 2008 vs March 2020 comparison, (10) three-signal-layer diagnostic.

**SOFR-OIS naming audit (raised by user):** legacy "SOFR-OIS" used loosely in the deck is imprecise. Future substrate should use "SOFR-term-vs-OIS basis" (for the tenor/funding-friction read) or "EFFR-SOFR" (for the bank-funding-stress read). Standardization cleanup pass queued.

**Process changes filed this session:**

- **2026-07-26 — Two-population conflation pattern:** when a partially-right probe answer has the *direction* right but the *population* or *sign* wrong, the partial-right response is itself data that the population distinction wasn't anchored. The carry-vs-basis population distinction is the Block 023 worked example. Codified in `~/.hermes/skills/finance/macro-mentor/references/carry-vs-basis-population-distinction.md`.
- **2026-07-26 — Diagnostic probe re-anchor rule (Session 31 → Session 32 applied):** open diagnostic probes that aggregate prior probes' substrate need a 2-3 sentence re-anchor of the substrate the probe is aggregating. Substrate landed cleanly with the velocity-vs-shape distinction as the diagnostic.
- **2026-07-26 — SOFR-OIS naming audit:** legacy "SOFR-OIS" replaced in Session 32 substrate with "SOFR-term-vs-OIS basis" or "EFFR-SOFR" depending on context. Standardization cleanup pass queued.

**Status transitions:**

- FX — CIP / UIP: Working+ (no grade change, expanded substrate)
- FX — CIP negative basis = balance-sheet cost: Working+ (no grade change)
- FX — Post-GFC structural basis = 24/7 constraint: Working+ (no grade change)
- FX — Cross-currency basis spread = relative carry-trade scale: Working+ (no grade change)
- FX — Term structure short-end widest = velocity: Working+ (no grade change)
- FX — BOJ exit second-order on basis = demand-side compression: **Working → Working+** (Target 2 diagnostic reinforced)
- FX — CIP deviations: three signatures (NEW): Untested → **Working+**
- FX — Carry trader vs hedged USD investor population distinction (NEW): Untested → **Working+**
- FX — UIP empirical failure: carry trade puzzle (NEW): Untested → **Working+**
- FX — 2008 vs March 2020 cross-currency basis comparison (NEW): Untested → **Working+**
- FX — Cross-currency basis diagnostic shape (NEW): Untested → **Working+**
- FX — Three-signal-layer diagnostic (Block 014 + 023 tie-in): Working+ (re-affirmed via Block 023 Target 4)
- FX — March 2020 scenario diagnostic (NEW): Untested → **Working+**

**Coverage tracker:** Block 023 → `covered`. Block 024 (FX central bank reaction functions) is next.

**Pre-read for Block 024 (assigned at this session close, per protocol):**

- BIS Papers — central bank swap line network: McCauley + Schenk (2020) "Central bank swap lines and cross-border bank flows" (or earlier McCauley + Schenk 2018) — ~20 min
- Borio et al. (2016) "FX intervention and the global cycle" — abstract + intro (already noted as candidate from Block 014) — ~15 min
- ECB / Fed / BOJ official communications on dollar swap lines (2013, 2020 activations) — ~10 min
- Skip: Detailed mechanical FX option pricing (Block 029 territory), EM-specific FX intervention (Block 028 territory)
- **Total: ~45 min, [thematic].**

**Pointer:** Block 023 → done. Block 024 → next. `competence-map.md` updated (8 new entries + 1 upgrade + 3 process changes). `coverage-tracker.md` updated (Block 023 → covered). 10 atomic Anki cards pushed + synced. Reference file `~/.hermes/skills/finance/macro-mentor/references/carry-vs-basis-population-distinction.md` created.

## Carry-forward to next block

Block 023 is the formal Phase 1 FX start. Cross-currency basis substrate from Block 014 is the foundation. Block 024 (FX central bank reaction functions) builds on the CIP/UIP framework by asking what happens when central banks intervene against persistent basis deviations.

**Block 023 status:** COVERED. All four targets landed at Working+. 10 atomic Anki cards pushed in Session 32. Reference file `~/.hermes/skills/finance/macro-mentor/references/carry-vs-basis-population-distinction.md` created.

**Pre-reads for Block 024 (assigned at Session 32 close, per protocol):**
- McCauley + Schenk (2020) "Central bank swap lines and cross-border bank flows" (or earlier McCauley + Schenk 2018) — ~20 min
- Borio et al. (2016) "FX intervention and the global cycle" — abstract + intro — ~15 min
- ECB / Fed / BOJ official communications on dollar swap lines (2013, 2020 activations) — ~10 min
- Skip: Detailed mechanical FX option pricing (Block 029 territory), EM-specific FX intervention (Block 028 territory)
- **Total: ~45 min, [thematic].**

**Carry-forward items for Block 024:**
- Block 023 substrate at Working+ across all four targets — Block 024 should reference the cross-currency basis diagnostic when discussing CB swap lines
- Three-signal-layer diagnostic (Block 023 Target 4) — Block 024 should apply to which CB facility activation = which layer broke
- Three signatures of CIP opening (acceleration, cross-section break, term-structure distortion) — Block 024 will see these manifesting as CB responses to persistent basis deviations

**Block 023 close protocol — `cohort-023-closed-2026-07-26.md` resume file created in `_session-state/`.**