CAIIB BFM Forex Calculations — All 7 Question Types with Worked Examples
Quick Answer: CAIIB BFM forex calculations cover 7 recurring question types: cross rates, forward rates from swap points, forward premium/discount %, interest rate parity, merchant rates (TT buying/selling), bill buying rate, and arbitrage. Together these account for approximately 30–35 marks in BFM. This guide works through each type with a step-by-step example in the exact format IIBF uses.
CAIIB BFM Forex Calculations — All 7 Question Types with Worked Examples
BFM’s forex module is the one that separates candidates who pass from those who don’t. Not because the mathematics is difficult — it isn’t. The problem is that most bankers have never worked in treasury or a forex desk, so the vocabulary alone is unfamiliar: bid-ask spreads, swap points, TT rates, interest rate parity. Once you understand what each term means and work through the problem sequence, you’ll find that every forex question follows one of seven patterns. Recognise the pattern; apply the formula; move on.
This guide covers all seven patterns with complete worked examples. Work through each section with a calculator. By the end, forex will be the most predictable — and highest-scoring — part of BFM.
Foundation — What Every CAIIB Forex Question Assumes You Know
Direct vs Indirect Quote
Direct Quote (India’s convention): Price of 1 unit of foreign currency in INR.
Example: USD/INR = 83.50 → 1 USD costs ₹83.50
Indirect Quote: Price of 1 unit of INR in foreign currency.
Example: INR/USD = 0.01198 → ₹1 costs $0.01198
Bid and Ask (Buy and Sell)
Every forex quote has two rates:
Bid (lower): Bank BUYS foreign currency (customer sells FC)
Ask/Offer (higher): Bank SELLS foreign currency (customer buys FC)
Bank buys USD @ 83.50
Bank sells USD @ 83.60
Spread = 83.60 − 83.50 = 0.10
Memory aid: Bank always wins — buys cheap, sells dear.
Premium vs Discount
Comparing forward rate to spot rate (in USD/INR terms):
- USD at Premium: Forward rate > Spot rate
(USD costs more INR in future → INR weakens) - USD at Discount: Forward rate < Spot rate
(USD costs fewer INR in future → INR strengthens)
Swap Points (Forward Margin)
Swap points are the difference between spot and forward rates, quoted separately in paise (for USD/INR).
→ ADD to spot → USD at Premium
If swap points: 45 / 35 (descending)
→ SUBTRACT from spot → USD at Discount
The 7 IIBF Forex Question Types
| # | Question Type | Est. Questions | Difficulty |
|---|---|---|---|
| 1 | Cross Rate | 4–5 | Easy |
| 2 | Forward Rate from Swap Points | 4–5 | Easy |
| 3 | Forward Premium / Discount % | 3–4 | Easy |
| 4 | Interest Rate Parity (Forward from Interest Rates) | 4–5 | Medium |
| 5 | Merchant Rates — TT Buying & Selling | 4–5 | Medium |
| 6 | Bill Buying Rate | 3–4 | Medium |
| 7 | Covered Interest Arbitrage | 2–3 | Hard |
Type 1 — Cross Rate Calculation
A cross rate is the exchange rate between two currencies derived from their rates against a common third currency (usually USD). IIBF gives you two pairs and asks you to find the third.
Formula
→ GBP/INR = GBP/USD × USD/INR = B × A
For bid-ask:
GBP/INR bid = GBP/USD bid × USD/INR bid
GBP/INR ask = GBP/USD ask × USD/INR ask
Worked Example
Q: USD/INR = 83.50/83.60 EUR/USD = 1.0800/1.0810. Find the EUR/INR rate.
EUR/INR bid = EUR/USD bid × USD/INR bid
= 1.0800 × 83.50 = 90.18
EUR/INR Ask (bank sells EUR):
EUR/INR ask = EUR/USD ask × USD/INR ask
= 1.0810 × 83.60 = 90.37
EUR/INR = 90.18 / 90.37
Type 2 — Forward Rate from Swap Points
Swap points (forward margins) are added to or subtracted from the spot rate to get the forward rate. The rule: if swap points are ascending (lower/higher), ADD. If descending (higher/lower), SUBTRACT.
Formula
Forward Bid = Spot Bid + Swap Bid
Forward Ask = Spot Ask + Swap Ask
Swap points DESCENDING (45/35) → Discount → SUBTRACT
Forward Bid = Spot Bid − Swap Bid
Forward Ask = Spot Ask − Swap Ask
Worked Example — Premium (Ascending Swap Points)
Q: Spot USD/INR = 83.50/83.60. 3-month forward margin = 35/45 paise. Find the 3-month forward rate.
Forward Bid = 83.50 + 0.35 = 83.85
Forward Ask = 83.60 + 0.45 = 84.05
3-month Forward USD/INR = 83.85 / 84.05
Note: Swap points are quoted in paise — divide by 100 to convert to rupees (35 paise = ₹0.35)
Worked Example — Discount (Descending Swap Points)
Q: Spot USD/INR = 83.50/83.60. 3-month forward margin = 45/35 paise. Find the 3-month forward rate.
Forward Bid = 83.50 − 0.45 = 83.05
Forward Ask = 83.60 − 0.35 = 83.25
3-month Forward USD/INR = 83.05 / 83.25
Type 3 — Forward Premium / Discount %
Given a spot rate and forward rate, calculate the annualised premium or discount. This tests whether you understand what the forward rate implies about the relative strength of two currencies.
Formula
[(F − S) / S] × (12 / n) × 100
Where: F = Forward rate, S = Spot rate, n = months
Positive result → Premium (FC appreciating)
Negative result → Discount (FC depreciating)
Worked Example
Q: Spot USD/INR = 83.50. 3-month forward = 84.50. Calculate the annualised forward premium on USD.
= [1.00 / 83.50] × 4 × 100
= 0.011976 × 400
= 4.79% per annum
USD is at a forward premium of 4.79% p.a. → INR is expected to depreciate against USD.
IIBF Reverse Question:
Q: Spot = 83.50. USD is at 6% p.a. premium. Find the 6-month forward rate.
Forward = Spot × (1 + 0.03) = 83.50 × 1.03 = 85.005 ≈ 85.01
Type 4 — Interest Rate Parity (Forward Rate from Interest Rates)
Interest Rate Parity (IRP) states that the forward rate is determined by the interest rate differential between two countries. If Indian interest rates are higher than US rates, INR weakens forward (USD at premium). This is the theoretically derived forward rate.
Formula (Covered IRP)
Where:
F = Forward rate (USD/INR)
S = Spot rate (USD/INR)
r_d = Domestic (India) interest rate
r_f = Foreign (US) interest rate
t = Time in years (or fraction)
Worked Example
Q: Spot USD/INR = 83.50. India interest rate = 8% p.a. US interest rate = 5% p.a. Calculate the 6-month forward rate.
F = 83.50 × [(1 + 0.08 × 0.5) / (1 + 0.05 × 0.5)]
= 83.50 × [(1 + 0.04) / (1 + 0.025)]
= 83.50 × [1.04 / 1.025]
= 83.50 × 1.01463
= 84.72
6-month Forward Rate = USD/INR 84.72
Verification: India rate > US rate → INR weakens → forward > spot ✓
Type 5 — Merchant Rates: TT Buying & TT Selling
Merchant rates are the rates banks quote to their retail/corporate customers — they differ from interbank rates by an exchange margin. TT (Telegraphic Transfer) rates are used for electronic transfers where there is no transit period.
Formulas
= Spot Bid − Exchange Margin
(Bank buys FC from customer)
= Spot Ask + Exchange Margin
(Bank sells FC to customer)
Exchange Margin = Spot Rate × Margin % · Typical margin: 0.10% to 0.20%
Worked Example
Q: Interbank USD/INR spot = 83.50/83.60. Exchange margin = 0.15%. Calculate TT Buying and TT Selling rates.
Margin = 83.50 × 0.15% = 83.50 × 0.0015 = 0.1253
TT Buying = 83.50 − 0.1253 = 83.3747 → 83.37 (round down — bank’s interest)
TT Selling Rate (bank sells USD to importer):
Margin = 83.60 × 0.15% = 83.60 × 0.0015 = 0.1254
TT Selling = 83.60 + 0.1254 = 83.7254 → 83.73 (round up — bank’s interest)
TT Buying = 83.37 · TT Selling = 83.73
Type 6 — Bill Buying Rate
When an exporter presents a foreign currency bill (export document) to the bank, the bank buys it at the Bill Buying Rate — which is lower than the TT Buying Rate because the bank has to wait for the transit period (time for funds to arrive from overseas) and loses interest during that period.
Formula
Transit Interest = TT Buying Rate × Interest Rate × (Transit Period / 365)
(Transit period = time for overseas remittance to arrive, typically 20–25 days)
Worked Example
Q: TT Buying Rate = 83.37. Transit period = 25 days. Interest rate = 12% p.a. Find the Bill Buying Rate.
= 83.37 × 12% × (25/365)
= 83.37 × 0.12 × 0.06849
= 83.37 × 0.008219
= 0.6851
Bill Buying Rate:
= TT Buying − Transit Interest
= 83.37 − 0.6851
= 82.6849 → 82.68 (round down — bank’s interest)
Bill Buying Rate = 82.68
Type 7 — Covered Interest Arbitrage
Arbitrage questions ask: given spot rate, forward rate, and interest rates in two countries, is there a profitable riskless trade? If the actual forward rate differs from the IRP-implied forward rate, arbitrage profit exists.
Decision Rule
F_implied = S × [(1 + r_d × t) / (1 + r_f × t)]
Step 2: Compare F_implied with actual forward rate F_actual
If F_actual > F_implied → Forward FC is overpriced → Sell FC forward (borrow in FC, invest in India)
If F_actual < F_implied → Forward FC is underpriced → Buy FC forward (borrow in India, invest in FC)
If F_actual = F_implied → No arbitrage possible
Worked Example
Q: Spot USD/INR = 83.50. 6-month forward = 85.00. India rate = 8% p.a., US rate = 5% p.a. An investor has ₹10,00,000. Is arbitrage possible? If yes, calculate profit.
F_implied = 83.50 × [(1 + 0.08 × 0.5) / (1 + 0.05 × 0.5)]
= 83.50 × [1.04 / 1.025] = 83.50 × 1.01463 = 84.72
Step 2 — Compare:
F_actual = 85.00 > F_implied = 84.72
→ Forward USD is OVERPRICED → Sell USD forward (borrow USD, invest in India)
Step 3 — Execute arbitrage:
• Convert ₹10,00,000 to USD at spot: 10,00,000 / 83.50 = $11,976.05
• Invest in US at 5% p.a. for 6 months: $11,976.05 × 1.025 = $12,275.45
• Sell $12,275.45 forward at 85.00: $12,275.45 × 85.00 = ₹10,43,413
Step 4 — Cost of INR borrowing:
₹10,00,000 at 8% for 6 months = ₹10,00,000 × 1.04 = ₹10,40,000
Arbitrage Profit = ₹10,43,413 − ₹10,40,000 = ₹3,413
BFM Forex — Formula Quick Reference
| Calculation | Formula | Key Rule |
|---|---|---|
| Cross Rate (bid) | FC1/FC3 bid = FC1/FC2 bid × FC2/FC3 bid | Multiply bids for bid, asks for ask |
| Forward (Premium) | Forward = Spot + Swap Points | Ascending swap points → ADD |
| Forward (Discount) | Forward = Spot − Swap Points | Descending swap points → SUBTRACT |
| Premium % (annualised) | [(F−S)/S] × (12/n) × 100 | n = number of months forward |
| IRP Forward Rate | F = S × (1+r_d·t) / (1+r_f·t) | r_d > r_f → F > S (FC at premium) |
| TT Buying Rate | Spot Bid − (Spot Bid × Margin%) | Round DOWN (bank’s benefit) |
| TT Selling Rate | Spot Ask + (Spot Ask × Margin%) | Round UP (bank’s benefit) |
| Transit Interest | TT Buying × Rate × (Days/365) | Use actual days; divide by 365 |
| Bill Buying Rate | TT Buying Rate − Transit Interest | Always less than TT Buying Rate |
| Forward Bill Selling Rate | TT Selling + Forward Margin (premium) | For import LC at forward rate |
Frequently Asked Questions — BFM Forex
How many forex questions appear in the actual CAIIB BFM exam?
Forex typically accounts for 30–40 questions out of 100 in BFM — it is the dominant topic in the paper. Module A (Treasury and Forex Management) is BFM’s heaviest module by mark weight. Missing forex completely makes it essentially impossible to clear BFM. Conversely, mastering all 7 question types gives you a near-guaranteed 25–30 marks before touching other modules.
What is the most common forex mistake candidates make?
Confusing bid and ask from the bank’s perspective vs the customer’s perspective. Remember: the bank always wins — it buys cheap (bid) and sells dear (ask). If a customer is buying USD, the bank is selling USD, so the customer gets the bank’s SELLING (ask) rate. If a customer is selling USD (e.g., an exporter), the bank is buying, so the customer gets the BUYING (bid) rate minus margin. Always identify who is buying and who is selling before applying the rate.
Do I need to memorise the exact exchange margin percentages for the exam?
No — IIBF always provides the exchange margin in the question. What you need to know is the methodology: which base rate to apply it to (spot bid for buying, spot ask for selling), whether to add or subtract, and the rounding convention. Practice the calculation method, not the specific margin percentages.
How much time should I spend on forex during BFM preparation?
10–12 days of your BFM preparation, plus daily maintenance practice of 2–3 forex problems per day throughout your entire prep period. Forex calculation skill decays faster than concept memory — if you do all the forex problems in week 1 and then don’t touch it until the exam 2 months later, you’ll have forgotten the sequence. Daily practice of 10–15 minutes keeps the steps automatic.
Is a calculator allowed for BFM forex questions?
Yes — IIBF provides an on-screen calculator for CBT exams. All BFM numerical questions, including forex, can use the calculator. The skill tested is the formula sequence and methodology — not mental arithmetic. Know which numbers go where, and let the calculator handle the multiplication and division.