LO 1a — Exam Question Patterns & Answer Frameworks

หน้านี้รวบรวม pattern คำถามที่ออกซ้ำๆ ใน LO 1a (Fixed Income Investments) พร้อม template คำตอบและ insight จากข้อสอบเก่า มาจาก keynote-gem-lo-1a

🧪 Interactive Labs (LO 1a)

ฝึกใน browser ได้เลย:

Mortgage Basics I — Geltner Ch.16 — 13 modules · 5-dim Resi vs Comm contrast · live foreclosure pecking-order waterfall · 14 mortgage covenant identifier (★ exam-fav-4 highlighted) · borrower’s put-option payoff diagram · Geltner 3-scenario strategic-default lab reproducing $9.1 Mw or k o u t /$ 0.1M / $1.5M surplus split · 10 verbatim past-exam drills (S2023 Q6 a/b/c · F2021 Q6 a/b/c · F2020 Q2(a) · F2024 Q14(a) · S2024 Q5(a)) · 45 flashcards · A4 cheat sheet.

Private Corporate Debt Primer Lab (INV101-101-25) — 16 modules · Cliffwater 5-component premium stacker (Mar-2022 13.6%) · Distressed Recovery Calc (45%→par→30.5% IRR) · Mezzanine 4-component return · Cov-Lite trend (1%→91%) · Drill Arena 12 verbatim drills (F2024 Q2 + S2022 Q13).

High-Yield Bond Primer Lab (INV101-102-25) — 16 modules · Rating Ladder · MWC calculator reproducing **F2022 Q8(b) → $114, 611 * * \cdot P I K t o gg l e l i v ec a l c \cdot B o n d M a t h L ab (Y TM / Y TC / Y T W + a ccr u e d$ 1,787.50 worked example) · Bondholder Protections (F2020 Q3(d) drill) · 10-drill Arena.

Question Type Distribution

ดู distribution ของ verb ต่างๆ ใน LO 1a — Compare and Contrast ออกบ่อยที่สุด ส่วน Calculate (Excel) เป็น trend ใหม่ที่เพิ่งโผล่ใน F2025 Q1 ต้องเตรียมตัวให้ดี

Type	Frequency	Example Exam References
Compare and Contrast	ออกบ่อยสุด	Spring 2023 Q6, Spring 2024 Q5, Fall 2024 Q14, Spring 2022 Q13, Fall 2024 Q2, Fall 2022 Q8, Fall 2020 Q3, Fall 2025 Q1(a)
Critique a Statement	ออกบ่อย	Spring 2024 Q5, Fall 2023 Q12, Spring 2022 Q17, Fall 2024 Q2, Fall 2025 Q1(e)
Describe / Explain	ปานกลาง	Fall 2022 Q8, Fall 2023 Q11, Fall 2025 Q1(b)
Recommend / Assess	ปานกลาง	Fall 2020 Q2, Fall 2020 Q3, Fall 2024 Q14
Calculate (Excel)	สูง (trend ใหม่)	Fall 2025 Q1(c)(d) — PSA cash flows + CMO tranche allocation

Favorite Comparison Pairs

คู่เปรียบเทียบเหล่านี้ ออกซ้ำๆ ต้องเตรียมพร้อมก่อนเข้าห้องสอบ:

Residential vs. Commercial Mortgages (Spring 2023 Q6, Spring 2024 Q5, Fall 2024 Q14)
Private Debt vs. High-Yield Bonds (Spring 2022 Q13, Fall 2024 Q2)
Make-Whole Call vs. Fixed-Price Call (Fall 2022 Q8)
Assignment vs. Participation (Fall 2020 Q3)
IG Bonds vs. HY Bonds / Leveraged Loans (กรอบทั่วไป)
Asset Types for Liability Cash Flow Matching (Fall 2025 Q1 — zeros vs. coupons vs. RMBS สำหรับ liability รายเดือนแบบ non-interest-sensitive)

Answer Template 1: Compare and Contrast

โครงสร้าง: Introduction → Dimensions → Conclusion/Portfolio Role

Introduction: Define A and B briefly. (1 sentence)
  "Private Debt and High-Yield (HY) Bonds are both speculative-grade credit
  instruments, but they differ significantly in their structure, market,
  and covenant protections."

Comparison (use clear dimensions):
  • Market & Liquidity: A is... B is...
  • Coupon Structure: A is... B is...
  • Security & Seniority: A is... B is...
  • Covenants: A has... B has...
  • Transparency & Sourcing: A has... B has...

Conclusion/Portfolio Role: (Crucial — always include!)
  "For an insurer with long-term, illiquid liabilities, Private Debt is
  often preferred. It offers an illiquidity premium, stronger covenant
  protection, and its floating-rate nature is attractive in a rising-rate
  environment."

Exam Tip

Conclusion ที่โยงกลับไปที่ portfolio context คือจุดที่ได้แต้มมากที่สุด อย่าหยุดแค่ list ความต่าง — ต้องบอกเสมอว่า asset ไหนเหมาะกับ scenario นั้นและทำไม

Answer Template 2: Critique a Statement

โครงสร้าง: Verdict → Core Concept → Mechanism → Implication

1. State Agreement/Disagreement: Start with a clear verdict.
   "The statement is incorrect. Tranche B is considerably more risky
   than Tranche A."

2. Explain "Why" using Core Concepts:
   "This is due to the subordination inherent in the CMBS structure.
   Tranche B is the first-loss (junior) tranche."

3. Define the Mechanism:
   "Credit losses from defaults in the underlying mortgage pool are
   allocated via a cash flow waterfall. All losses are first absorbed
   by Tranche B until its principal is completely written down."

4. Conclude with the Implication:
   "Therefore, Tranche A is protected from all losses up to [X%].
   Tranche B has a much higher probability of loss and loss severity,
   justifying its higher yield."

Exam Tip

สำหรับ Critique question — ตอบ yes/no verdict ชัดๆ ตั้งแต่ต้น แล้วตามด้วย mechanism คือสิ่งที่แยกคำตอบเก่งจากธรรมดา ตอบกั๊กๆ ไม่ commit จะเสียแต้ม

Past Exam Analysis

Fall 2023, Q11 — CMBS/RMBS Comparison

(a) Differences: Diversification, creditworthiness basis (NOI vs. DTI/FICO), prepayment risk (CMBS low / RMBS high), economic drivers.
(b) Tranche quality: Tranche A is “much safer” due to 20% credit subordination. Breakeven = 40 loan defaults before A is impacted.
(c) Rising rate risks: Lower property values → higher default → balloon refinancing risk.
(d) Mitigation: Diversify pool, enhance underwriting (lower LTV), more tranches (increase subordination).
Takeaway: เชื่อม tranche safety กับ subordination แบบเชิงปริมาณ และเชื่อมเรื่อง macro กับผลกระทบเฉพาะ asset

Fall 2022, Q8 — Corporate Bonds

(a) MWC vs. Fixed-Price: MWC call price varies inversely with rates (good for investor); Fixed is static (bad for investor). MWC used on IG; Fixed on non-IG.
(d) Deferred coupon types: Deferred-Interest, Step-Up, PIK — all conserve cash for the issuer.
Takeaway: ต้องรู้ implication ของแต่ละ feature ต่อ investor MWC = ดี Fixed Call = แย่

Fall 2024, Q2 — Private Debt vs. HY Bonds

(a) Compare on return, risk, market, cash flow dimensions.
(b) Recommend HY Bonds when the requirement is transparency and liquidity (PD fails here).
(c) Critique: “CDS eliminates interest rate risk” is incorrect — CDS premium and loss PV are rate-sensitive.
Takeaway: จับคู่ recommendation กับ goal ที่โจทย์บอก อย่า default-recommend Private Debt ทันทีเมื่อโจทย์ต้องการ liquidity

Fall 2025, Q1 — RMBS, CMO Sequential Tranches & Cash Flow Matching (8 pts)

ข้อที่ weight สูงสุดในข้อสอบ ทดสอบ MBS mechanics ตั้งแต่ต้นจนจบ: risk identification → liability matching → PSA cash flow calculation → CMO tranche allocation → critique ของ investment proposal

(a) Contrast risks of Agency RMBS, PQR coupon bond, PQR zeros vs. Treasury → Agency: prepayment risk; PQR bonds: credit/spread/event risk; Treasury/Agency: sovereign risk. Performance: as expected. Few mentioned sovereign risk.
(b) Best security for liability matching (non-interest-sensitive monthly CFs) → PQR zeros: monthly cash flows, no prepayment risk, cheapest upfront. Performance: below expectations — หลายคนเลือกถูกแต่อธิบายเหตุผลครบไม่ได้
(c) Calculate RMBS pass-through cash flows at 210% PSA in Excel → SMM from CPR, scheduled principal, prepayment, interest, total CF. Performance: below expectations — ผิดสูตรกันเพียบ
(d) Calculate CMO Tranche 2 cash flows (sequential pay) in Excel → T1 absorbs all principal first, then T2, then T3. Performance: poor — เว้นว่างเยอะ หรือไม่ก็เข้าใจ sequential tranches ผิดตั้งแต่พื้นฐาน
(e) Critique: “$4.5M Tranche 2 matches liability” → Valid only under 210% PSA assumption. In reality, prepayment varies with interest rates → cash flows deviate → fails non-interest-sensitive liability guideline. Performance: below expectations

Exam Tip — Cash Flow Matching Critique Pattern

Template ของ Q1(e): “The proposal is valid only under condition X. Condition X is unrealistic because Y. Therefore, the asset fails guideline Z.” Pattern นี้โผล่ทุกครั้งที่มีคนเสนอใช้ asset ที่ sensitive ต่อดอกเบี้ยมา back liability ที่ non-interest-sensitive

Exam Tip — PSA Excel Pipeline

Pipeline ของ PSA calculation ต้องเป็น muscle memory: PSA speed → CPR → SMM → Scheduled Principal → Prepayment → Interest → Total CF ฝึกสร้าง model นี้ใน Excel จากศูนย์ — มันคุ้ม 4 จาก 8 แต้มเลย

Takeaway: Q1 คือข้อที่หนักที่สุดในแง่ computation ของข้อสอบ ส่วน Excel (c) กับ (d) รวมกัน 4 แต้ม ถ้าสร้าง PSA cash flow model จากศูนย์ไม่ได้ — เสียไป 8% ของข้อสอบทั้งหมด

Spring 2023, Q6 — Mortgages

(a) 3 differences: Size/volume, income source, borrower type.
(b) 4 covenants: Promise to Pay, Due-on-Sale, Good Repair, Acceleration Clause.
(c) Borrower’s put option: Non-recourse → borrower can default and “sell” property at outstanding loan balance.
Takeaway: Non-recourse put option เชื่อม legal structure กับ financial implication — concept ที่ exam ชอบมาก

Common Pitfalls

Pitfall	Correct Understanding
สับสนระหว่าง CLOs และ CMBS	CLOs = backed by leveraged-loans (corporate risk). CMBS = backed by mortgages (real estate risk).
ลืม “Bankruptcy Remote”	Securitization (CLO, CMBS, RMBS) ใช้ SPV ที่แยก legal จาก originator Model answer พูดเรื่องนี้บ่อยมาก
”CMBS has high prepayment risk”	ผิด CMBS มี prepayment risk ต่ำ (defeasance/lockouts) แต่มี default/balloon risk สูง ที่ prepayment risk สูงคือ RMBS ต่างหาก
”MBS has prepayment risk” (กว้างไป)	ต้องอธิบาย ทำไม มันแย่: principal คืนตอน rate ต่ำ (reinvestment risk) + duration ขยายตอน rate สูง (extension risk) = negative convexity
”All call options are bad for investors”	ผิด Make-Whole Call ชดเชย investor ที่ rate ต่ำในปัจจุบัน — ดีกว่า Fixed-Price Call เยอะ
สับสน PIK vs. Step-Up	PIK = option ที่จะจ่ายเป็น in-kind ก็ได้ Step-Up = coupon เพิ่มแบบ scheduled ตามกำหนด

Critical Keywords for Written Answers

ใช้คำเหล่านี้แบบ precise ในคำตอบ exam:

Term	Context
Subordination	CMBS/CLO — junior absorbs losses first to protect senior
Credit Enhancement	Internal (subordination, OC, excess spread) vs. External (insurance, LOC)
Negative Convexity	MBS — underperforms in both rising and falling rate scenarios
Make-Whole Call	Corp bonds — favorable to investors, PV-based call price
PIK (Payment-in-Kind)	HY/Private Debt — issuer option to pay with more debt
Covenant-Lite	Lev Loans — fewer restrictions, riskier for lender
Non-Recourse	Commercial mortgages — lender limited to property, creates borrower’s put
Bankruptcy Remote	CLO/CMBS — SPV protects assets from originator bankruptcy
Defeasance	Commercial mortgages — prepayment protection via Treasury replication

Comprehensive Past Exam Database: LO 1a (Fall 2020 – Fall 2024)

30 คำถามที่ SOA รวบรวมไว้ ด้านล่างคือ breakdown ของทุกข้อ LO 1a พร้อม key answer points ใช้สำหรับทบทวนแบบเจาะจงก่อน exam

F2020 Q2 — CMBS Structure & Holding Period Return

LO: 1a | Source: Geltner Ch 16, Fabozzi Ch 23

Part	Topic	Key Answer Points
(a)	Permanent vs. Construction loans	Construction: higher default risk, shorter term. Permanent: higher interest rate risk, longer term.
(b)(i)	LTV recommendation	CMBS-I LTV = 250M/400M = 62.5%. CMBS-II LTV = 300M/450M = 66.7%. Recommend CMBS-I (lower LTV = less levered).
(b)(ii)	WAM recommendation	CMBS-I WAM = (4×2×50 + 6×3×50)/250 = 5.2 yrs. CMBS-II WAM = (7×100 + 10×200)/300 = 9 yrs. Recommend CMBS-I (6-year liability → 5.2 yr WAM is the better match).
(c)	Subordination at start of Year 5	After 2 mortgages mature: Pool = $150 M, T r an c h e A =$ 100M. Subordination = $50 M /$ 150M = 33%.
(d)	HPR Plan A vs. Plan B	Mortgage coupon = 7% (back-calculate from tranche coupons). Plan A: E[CF] = 60%× $46.5 M + 40$ 52.5M = $48.9 M \to H PR = ($ 48.9M − $48 M) /$ 48M = 1.88%. Plan B: 2.5% T-Bill. Recommend Plan B.

Exam Tip — Subordination Calculation

Subordination = (Pool par − Senior par) / Pool par มันเปลี่ยนตามเวลาเมื่อ mortgage maturity ลงหรือ principal ถูกจ่ายคืน Year 5 calculation ต้อง update ทั้ง pool par และ senior par ก่อน — เป็น 2-step process ที่หลายคนพลาด

Exam Tip — Mortgage Interest Rate Back-Calculation

Coupon ของ underlying mortgages ไม่ได้ให้มาตรงๆ ต้อง derive: solve for rate ที่ทำให้ (Tranche A coupon × A par + Tranche B coupon × B par + IO coupon × IO notional) = mortgage coupon × pool balance

F2020 Q3 — Leveraged Loans, CLOs, HY Bonds

LO: 1a | Source: Fabozzi Ch 11, HY Bond Primer

Part	Topic	Key Answer Points
(a)	Assignment vs. Participation	Assignment: transfers ownership, best price, needs borrower consent. Participation: lender of record unchanged, creates extra credit risk for buyer, worse price. Recommend Assignment when buyer/borrower relationship is good.
(b)	CLO value-add for ABC	(1) Remove leveraged loans from balance sheet → reduces regulatory capital. (2) Earn asset management fees as CLO manager.
(c)	Critique: equity tranche not risky because APR violated	Incorrect. APR violation occurs in corporate bankruptcies. CLO is a bankruptcy-remote SPV — it cannot go bankrupt. CLO cash flow waterfall strictly enforces seniority; APR never applies.
(d)	HY bond features for deteriorating borrower	Put provision: ✅ forces accelerated repayment. Call protection: ❌ only protects if borrower would call (no incentive when deteriorating). Bullet structure: ❌ same as call protection. Equity warrants: ❌ buying equity in a deteriorating firm is worthless.
(e)	HY Bonds vs. Leveraged Loans for credit/duration/recovery	HY Bonds recommended: most credit risk exposure (Statement I); longer maturities, fixed rate better for duration matching (Statement II); company can exploit APR violations in bonds to enhance recovery (Statement III).

Exam Tip — CLO Is Always Bankruptcy Remote

โผล่ซ้ำๆ (F2020 Q3, F2023 Q12) Key phrase ใน model answer: “CLO is a bankruptcy-remote entity — it cannot go bankrupt, either voluntarily or through the action of an aggrieved creditor.” จำให้ขึ้นใจ

F2020 Q16 — Repurchase Agreements & Dollar Rolls

LO: 1a | Source: Fabozzi Ch 60

Part	Topic	Key Answer Points
(a)(i)	Overnight repo mechanics	Bank sells (delivers) security to counterparty; agrees to buy back tomorrow at higher price (difference = interest at repo rate).
(a)(ii)	Why repo is cost-efficient	Repo rate < bank financing rate. From lender’s side: still attractive because secured and liquid.
(b)	Credit risk reduction in repo	(1) Haircut/Over-collateralization: lend less than market value; cushion against decline. (2) Mark-to-market: regular revaluation; margin deficit triggers additional collateral or cash.
(c)(i)	Dollar roll description	MBS-specific collateralized loan. Dealer only needs to return “substantially identical securities” (same coupon, issuer type, collateral type) — not the exact same securities. 100% financing (no haircut).
(c)(ii)	Repo vs. Dollar Roll differences	Dollar roll: (1) not exact same securities returned, (2) dealer keeps coupon and principal paid during loan period, (3) potentially cheaper financing due to flexibility given to dealer.

S2021 Q5 — Bond Pricing & Call Price Calculation

LO: 1a | Source: Fabozzi Ch 10

Setup: 2-year bond, semi-annual coupons, BEY = 3%. YTM = 4%, YTC = 6%. Called at end of Year 1.

Step 1: Price at issue (YTM = 4%, semi-annual discount rate = 2%):

Periods 1–4: coupon = 1.5, period 4 also returns par 100
Price = 98.10

Step 2: Find call price X (YTC = 6%, semi-annual = 3%):

Two remaining cash flows: coupon 1.5 at period 1, (1.5 + X) at period 2
1.46 + (1.5 + X) × 0.943 = 98.10
Call price X = $101.03

Exam Tip — YTC Calc Direction

ต้อง reverse-engineer call price ตั้ง PV equation ณ วันนี้ แล้ว solve for X Discount rate ใช้ YTC (ไม่ใช่ YTM) หลายคนใช้ rate ผิด

F2021 Q6 — Commercial Mortgage: Default Options

LO: 1a | Source: Geltner Ch 16

Part	Topic	Key Answer Points
(a)(i)	Non-litigious options	Transfer/assumption to new borrower; short sale (lender-approved sale by borrower); deed-in-lieu of foreclosure; loan restructuring/workout.
(a)(ii)	Litigious steps	(1) Sue for specific performance; (2) Sue for damages without invoking mortgage deed; (3) Invoke mortgage deed → foreclosure action.
(b)	Mitigate prepayment/credit risk at issue	(1) Remove prepayment clause; (2) Set very high prepayment penalties; (3) Lockout clause; (4) Defeasance (pay off via Treasury bond replication); (5) Require recourse / parent guarantee / additional collateral.
(c)	Borrower action in each scenario	Scenario 1 ( $1 Mp ro p er t y) : * * P a y * * — n e t f ro m s t a y in g i s$ 200K. Scenario 2 ( $850 K) : * * St r a t e g i c d e f a u lt * * — p ro p er t y (n e t o ff orec l os u re) =$ 700K < $800 Ko w e d; n e g o t ia t es ha re dd i ff ere n ce . S ce na r i o 3 ($ 700K): Foreclosure — property value below loan; simply walk away.

S2022 Q13 — Private Debt, PIK Notes, Event Risk

LO: 1a | Source: INV101-101-25, HY Bond Primer, Fabozzi Ch 10

Part	Topic	Key Answer Points
(a)	Private debt advantages over HY bonds	(1) Floating rate → less mark-to-market volatility; (2) More covenants → more secure; (3) Illiquidity premium; (4) Greater diversification; (5) Targets higher absolute returns.
(b)	PIK vs. bullet structure cash flows	Bullet: semi-annual coupons + par at maturity; fully predictable. PIK: during PIK period, issuer can pay coupon in cash OR issue new bonds; after PIK period, reverts to cash coupon only; equity clawback allows issuer to redeem % of bonds with equity proceeds (pays par + 1yr coupon).
(c)	Event risk from M&A activity	M&A in industrial sector can: (1) cause specific collateral bonds to decline in value (leverage increases post-merger); (2) cause general market spread widening for all industrial bonds → more collateral required → ZZZ gets downgraded.
(d)	Protective covenants against M&A	(1) Poison put: bondholder can force buyback → reduces acquisition attractiveness. (2) Maintenance of net worth clause: if merger leaves borrower with lower net worth, company must redeem bonds at par (valuable if market price < par).

S2022 Q17 — MBS: Prepayment, Negative Convexity, WAC

LO: 1a | Source: Fabozzi Ch 21

Part	Topic	Key Answer Points
(a)	Critique “MBS eliminates interest rate risk”	Incorrect. MBS has prepayment risk — borrowers can prepay. Duration of 15yr fixed-rate MBS < 15 years (because of prepayments). Creates duration mismatch. Also: fixed-rate MBS still exposed to non-parallel yield curve shifts.
(b)	Identify Security A (bond) vs. Security B (MBS)	Security B = MBS (negative convexity: when rates fall, price underperforms bond due to accelerated prepayments; when rates rise, price drops more due to extension). Security A = Fixed-Maturity Bond.
(c)	3 sources of WAC vs. pool coupon difference	(1) Base servicing; (2) Guarantee fees (G-fees) for credit insurance; (3) Excess servicing.
(d)(i)	Credit risk interpretation	Credit Score (lower = worse), LTV (higher = worse), DTI (higher = worse).
(d)(ii)	Which pool defaults more	MBS B: lower credit score (700 vs. 760), higher LTV (85% vs. 80%), higher DTI (40% vs. 30%). All three metrics point to higher default risk.

F2022 Q8 — Corporate Bond Features: Make-Whole Call, Tender, Deferred Coupons

LO: 1a | Source: Fabozzi Ch 10

Part	Topic	Key Answer Points
(a)	MWC vs. Fixed-Price Call	MWC: call price = max(par+½ coupon, PV at CMT+spread). Fixed: predetermined price. MWC used for IG (investor-friendly); Fixed used for non-IG. MWC: less upfront compensation needed.
(b)	MWC call price calculation	Remaining maturity at 7.5yr = 2.5yr. Interpolate CMT: 0.25×1Yr + 0.75×3Yr = 0.25×1.00 + 0.75×1.20 = 1.15%. Add 10bp spread = 1.25%. PV of $6 Kco u p o n s +$ 100K par at 1.25% using annuity factor 2.945: = 2.945×6,000 + 100,000×(1/(1.0125)^2.5) = *$114, 611 * . C a llp r i ce = ma x ($ 103,000, $114, 611) = * $ 114,611*.
(c)(i)	Tender offer price at end of Year 8	Remaining maturity = 2 years. Interpolate: 0.5×6MoCMT + 0.5×1YrCMT + 12bps spread. Discount 2 remaining coupon + par cash flows. = $109,852.
(c)(ii)	Advantages of tender offer	(1) Eliminates interest rate risk for both parties during offer window (fixed spread). (2) Can eliminate restrictive covenants. (3) Can target any or all of the issue. (4) Firm can increase price/extend window to boost participation.
(d)	3 deferred coupon bond types	(1) Deferred Interest (Zero): no coupons for 3–7yr, deep discount at issue. (2) Step-Up: low initial coupon, scheduled increase. (3) PIK: issuer option to pay cash or in-kind with bonds.
(e)	Correct incorrect statements	(i) Extendible reset bond: resets coupon to trade at predetermined price (not fixed spread). (ii) Modern sinking fund: money applied periodically to early redemption (not at maturity). (iii) HY bonds: below-IG debt instruments (not derivatives). (iv) Credit spread: reflects credit risk + liquidity premium + embedded options (not exclusively credit risk).

F2022 Q9 — Non-Agency RMBS

LO: 1a | Source: Fabozzi Ch 21

Part	Topic	Key Answer Points
(a)	Creditworthiness factors	(1) Credit score; (2) LTV; (3) Combined LTV (CLTV — includes second liens); (4) DTI / income ratios (front-end: housing payment/income, back-end: all debt/income); (5) Documentation.
(b)	RMBS capital structure features	(1) Floating coupon (matches ARM collateral); (2) Linear structure (one collateral group); (3) Sequential structure (senior tranches paid first); (4) Pro-rata structure; (5) Lockout period (subordinates locked from prepayments); (6) Trigger tests (delinquency, factor, credit support, cumulative loss); (7) Clean-up call provision.
(c)	Recommend credit enhancement	OC/XS (Overcollateralization / Excess Spread): appropriate for high-loss collateral like Option ARMs. Extra collateral creates first line of defense; excess spread (WAC > bond coupon) provides additional buffer. Stepdown date releases OC to junior bonds once performance criteria met.
(d)	Why prepayments slowed	(1) Lower property sales; (2) Fewer fires/disasters; (3) Less borrower defaults; (4) Less refinancing; (5) Note rate already below market rates.

S2023 Q6 — Mortgages: Types, Covenants, Put Option

LO: 1a | Source: Geltner Ch 16

(a) 3 differences (residential vs. commercial): Size/volume, income source (commercial: property income; residential: borrower income), borrower sophistication.
(b) 4 covenants: Promise to Pay, Due-on-Sale, Good Repair Clause, Acceleration Clause.
(c) Borrower’s put option: In non-recourse mortgage, borrower can default and effectively sell property to lender at outstanding loan balance. Lender cannot pursue other assets.

S2023 Q10 — Repo, Securities Lending, TIPS

LO: 1a | Source: Fabozzi Ch 60

Part	Topic	Key Answer Points
(a)	Repo construction	You (borrower) deliver Treasuries to Manager Y (lender), receive cash, invest cash, pay repo rate interest, receive coupon income from Manager Y, buy back at repurchase date. Note: amount earned from repo is uncertain and can be negative.
(b)	Securities lending construction	You (security lender) deliver Treasuries to Manager Z (security borrower), receive cash collateral, invest it, rebate part of investment income to Z, Z pays you coupon income you would have received, you return cash collateral when you reclaim securities.
(c)	TIPS risk premium	Risk premium = (1+nominal)/(1+TIPS real) − 1 − risk-adjusted BEI = (1.07/1.03) − 1 − 0.031 = 0.78% (or approximate: 7% − 3% − 3.1% = 0.9%).
(d)	Why TIPS over Treasuries	TIPS hedge against inflation; fixed real yield; low correlation to traditional assets; strategic ALM use when return objective is in real terms.

F2023 Q11 — CMBS vs. RMBS, Rising Rate Risks

LO: 1a | Source: Geltner Ch 16, Fabozzi Ch 23

Part	Topic	Key Answer Points
(a)	CMBS vs. RMBS differences	Loan diversity (CMBS more varied). Creditworthiness basis (CMBS: NOI, tenant mix, occupancy; RMBS: FICO, DTI, LTV). Prepayment risk (CMBS: low due to lockouts/penalties; RMBS: higher). Economic drivers differ (CMBS: business cycle; RMBS: consumer credit, housing market).
(b)	Tranche A vs. B credit quality	Tranche A: 20% credit support = $100 M b u ff er . O n l y im p a c t e d i f > 40 o f 100 l o an s d e f a u lt (v i r t u a ll y im p oss ib l e a t 1$ 100M. Same leverage exposure as underlying but concentrated — riskier than underlying.
(c)	Rising rate risk factors	(1) Lower property values → reduced collateral quality. (2) Refinancing risk: higher refinancing costs. (3) Increased probability of default as tenant cash flows squeezed by economic slowdown.
(d)	Mitigation strategies	(1) Diversify mortgage pool. (2) Enhance underwriting (lower LTV, higher DSCR). (3) More tranches / higher credit support for senior tranches.

F2023 Q12 — HY Bonds & CLO Cash Flow Structures

LO: 1a | Source: Fabozzi Ch 22, HY Bond Primer

Part	Topic	Key Answer Points
(a)	2 additional reasons for HY/CLO popularity	(1) Bank regulation post-GFC → banks retrenched → greater demand for non-bank private debt. (2) Liquidity risk concerns in short-term borrowing markets motivated alternative financing.
(b)	Cash flow structures	Deferred Interest: no coupons 3–7yr, deep discount, then higher coupons. Step-Up: low initial coupon, higher later; more initial cash than deferred. PIK: issuer option cash or in-kind bonds; preserves issuer liquidity; increases investor’s bond exposure and credit risk. CLO: issues multiple tranches, uses proceeds to buy loan pool; cash flows distributed by seniority waterfall; can call for funding commitments.
(c)	Justify CLO senior debt vs. HY bond at same yield	Diversification: CLO invests in many loans (not concentrated). Risk appetite: CLO allows investors to choose their tranche (senior gets safety, equity gets upside). Liquidity in default: par coverage test forces cash to pay senior principal first; subordination protects senior tranche.
(d)	Critique: CLOs have high bankruptcy risk	Incorrect. CLOs are bankruptcy-remote. Cannot go bankrupt voluntarily or through creditor action. Cannot be caught in another entity’s bankruptcy. Insolvency mechanics are contractually determined at origination.

S2024 Q5 — CMBS: Tranche Risk, Prepayment, Hedging

LO: 1a | Source: Geltner Ch 16, Fabozzi Ch 23

Part	Topic	Key Answer Points
(a)	Residential vs. commercial mortgages	Volume: residential = more numerous, smaller. Loan size: commercial = larger. Income: commercial = property generates income; residential = borrower income. Borrower: commercial = business professionals; residential = occasional buyers.
(b)	Critique “Tranche B similar risk to Tranche A”	Incorrect. Tranche B is first-loss — all credit losses are assigned to B until B is fully written down. B may have same default probability on underlying pool, but has much greater conditional loss severity.
(c)	Tranche amounts after prepayments	Total prepayments = 25× $0.5 M + 25 \times$ 0.25M = $18.75 M . A llp re p a y m e n t s f l o wt o T r an c h e A f i rs t (se q u e n t ia l) . T r an c h e A or i g ina lp a r = 100 \times$ 0.5M×75% = $37.5 M \to n e wp a r =$ 37.5M − $18.75 M = * $ 18.75M. Tranche B unchanged = $12.5M*.
(d)	Strategy balancing return vs. downside risk	Buy Credit Default Swap (CDS) on underlying loan pool — provides protection if loans default (which hits Tranche B first). Or: limit position size in Tranche B to cap potential loss.

F2024 Q2 — Private Debt Funds vs. HY Bonds

LO: 1a | Source: INV101-101-25, HY Bond Primer

Part	Topic	Key Answer Points
(a)	Compare vs. IG bonds: Private Debt vs. HY	Private Debt: higher yield; GP-skill-dependent risk (lower avg default); not traded/not rated (illiquid, opaque); loan coupon + fees, secondary market exists. HY Bonds: higher yield; higher default/credit risk; public market, rated (transparent, liquid); fixed or flexible coupon structures.
(b)	Recommend (senior mgmt wants transparency/liquidity)	HY Bonds: publicly traded, rated, more transparent default information, more liquid. Private debt fails on both criteria.
(c)	Critique: CDS eliminates interest rate risk	(1) Both expose seller/investor to credit risk of reference entity. (2) CDS has less cash outflow upfront (no principal). (3) CDS introduces counterparty risk. (4) CDS does NOT eliminate interest rate risk — PV of both premium leg and loss leg are rate-sensitive.

F2024 Q14 — CMBS: Securitization, Tranches, Moral Hazard

LO: 1a | Source: Geltner Ch 16, Fabozzi Ch 23

Part	Topic	Key Answer Points
(a)	4 differences: residential vs. commercial	(1) Residential smaller, more numerous. (2) Residential: no income from property (lender depends on borrower). (3) Residential: less sophisticated borrowers. (4) Commercial: more unique properties; residential more homogeneous. (5) Government involvement much greater for residential.
(b)	CMBS key players	Borrowers → Lenders → Investment Banks (package) → Trust (issues tranches) → Investors. Servicers handle collections and defaults, receive fee.
(c)	Tranche critique for life insurer	Tranche A: ✅ Senior, priority cash flows, protected by B. Appropriate for insurer. Tranche B: ❌ First-loss, default risk too high for life insurer. IO Strip: ⚠️ possible but volatile duration, low coupon. Recommend Tranche A.
(d)	Moral hazard & adverse selection in CMBS	Moral hazard: lenders who control underwriting quality immediately sell risk → incentive to loosen standards. Adverse selection: if CMBS lenders must charge higher rates → best borrowers go elsewhere → only riskier loans remain.

F2021 Q14 — Leveraged Loan Covenants

LO: 1a | Source: Fabozzi Ch 11

5 จุดประสงค์ของ covenant:

Capital preservation — กัน asset ไม่ให้ถูก strip ออกไป
Excess capital application — surplus cash flow ต้องเอาไปจ่ายหนี้
Business risk control — กันไม่ให้ทำ decision เอื้อ equity แต่ทำลาย lender
Performance monitoring — coverage/leverage ratio covenants
Reporting requirements — บังคับ budget projections internal reports

Cross-References

keynote-gem-lo-1a — source document
lo-1-curated-questions — full Q&A source with answer key essentials
corporate-bonds, high-yield-bonds, leveraged-loans, private-debt — speculative-grade trio + IG
mortgages, mortgage-backed-securities — mortgage asset classes
structured-credit-products — CLO/CMBS tranching
repo-financing — bond financing mechanisms

Ronram

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LO 1a — Exam Question Patterns & Answer Frameworks (ไทย)

LO 1a — Exam Question Patterns & Answer Frameworks

Question Type Distribution

Favorite Comparison Pairs

Answer Template 1: Compare and Contrast

Answer Template 2: Critique a Statement

Past Exam Analysis

Fall 2023, Q11 — CMBS/RMBS Comparison

Fall 2022, Q8 — Corporate Bonds

Fall 2024, Q2 — Private Debt vs. HY Bonds

Fall 2025, Q1 — RMBS, CMO Sequential Tranches & Cash Flow Matching (8 pts)

Spring 2023, Q6 — Mortgages

Common Pitfalls

Critical Keywords for Written Answers

Comprehensive Past Exam Database: LO 1a (Fall 2020 – Fall 2024)

F2020 Q2 — CMBS Structure & Holding Period Return

F2020 Q3 — Leveraged Loans, CLOs, HY Bonds

F2020 Q16 — Repurchase Agreements & Dollar Rolls

S2021 Q5 — Bond Pricing & Call Price Calculation

F2021 Q6 — Commercial Mortgage: Default Options

S2022 Q13 — Private Debt, PIK Notes, Event Risk

S2022 Q17 — MBS: Prepayment, Negative Convexity, WAC

F2022 Q8 — Corporate Bond Features: Make-Whole Call, Tender, Deferred Coupons

F2022 Q9 — Non-Agency RMBS

S2023 Q6 — Mortgages: Types, Covenants, Put Option

S2023 Q10 — Repo, Securities Lending, TIPS

F2023 Q11 — CMBS vs. RMBS, Rising Rate Risks

F2023 Q12 — HY Bonds & CLO Cash Flow Structures

S2024 Q5 — CMBS: Tranche Risk, Prepayment, Hedging

F2024 Q2 — Private Debt Funds vs. HY Bonds

F2024 Q14 — CMBS: Securitization, Tranches, Moral Hazard

F2021 Q14 — Leveraged Loan Covenants

Cross-References

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