Interest Rate Swaps - Interactive Explainer

1 What is a Swap?

Explained so simply, a golden retriever could understand it.

Imagine this: You have a pizza shop and pay rent that changes every month (sometimes $1,000, sometimes $1,500 — you never know). Your friend has a coffee shop and pays exactly $1,200 every month, no surprises. You HATE surprises. Your friend thinks rent will drop soon and wants to gamble on it. So you make a deal: you'll pay their fixed $1,200, and they'll pay whatever your changing rent is. That's a swap!

In finance terms:

A swap is an agreement between two parties to exchange payment streams. The most common type is an Interest Rate Swap (IRS) where one party pays a fixed interest rate and receives a floating (variable) rate — or vice versa.

They are traded OTC (Over-The-Counter) — meaning directly between parties, not on an exchange — and are highly customizable.

The Basic Swap Diagram

Has Fixed Rate Loan

Party A

Fixed

Thinks rates will FALL

Pays Floating →

← Pays Fixed

Has Floating Rate Loan

Party B

Float

Thinks rates will RISE

Key insight: No one actually lends money to the other. They just agree to pay each other's interest. Only the net difference changes hands each period. If fixed = 5% and floating = 4.5%, the fixed payer just sends 0.5% to the floating payer. Simple!

2 See It In Action

Drag the sliders and watch the money flow.

Fixed Rate (agreed in swap) 5.0%

Current Floating Rate (market) 4.0%

Notional Amount $10,000,000

Fixed Rate Payer

Party A

Pays 5.0% →

← Pays 4.0%

Floating Rate Payer

Party B

Net Payment

          $50,000
        

Party A pays Party B

Try this: Drag the floating rate above the fixed rate. See how the payment direction flips? That's the whole magic of swaps — when rates move, one party benefits and the other pays the difference.

3 The Classic Example

How Rich Bank and Green Corporation both save money through a swap.

The Setup: Borrowing Costs

Adjust each party's borrowing costs and the swap rate to see how comparative advantage and savings change:

Rich Bank (top credit)

Fixed rate 7.0%

Floating spread HIBOR + 0.0%

Green Corp (lower credit)

Fixed rate 8.0%

Floating spread HIBOR + 0.5%

	Fixed Rate	Floating Rate

The Swap

Swap Fixed Leg (Green → Rich) 7.4%

Swap Float Leg (Rich → Green) HIBOR + 0.0%

Mutually beneficial range: 7.00% – 7.50%

Cash Flow Diagram

Each party borrows where they're strongest, then swaps to get the exposure they actually want.

Bond Market

Lender

← 7.0% fixed

Rich pays lender

Rich Bank

Wants floating

← 7.4% fixed ←

Green pays Rich (swap)

→ HIBOR →

Rich pays Green (swap)

Green Corp

Wants fixed

HIBOR + 0.5% →

Green pays lender

Bank Market

Lender

Rich Bank's Net Borrowing Cost

HIBOR - 0.40%

Saves 0.40% vs HIBOR + 0.0%

7.4% received cancels 7.0% paid → +0.40% gain on fixed leg

Green Corp's Net Borrowing Cost

7.90%

Saves 0.10% vs 8.0%

HIBOR received cancels HIBOR in loan → only 0.5% float cost remains

Why does Rich receive fixed in the swap? Rich already PAYS 7.0% fixed to the bond market. To convert to floating, it needs to RECEIVE fixed in the swap (to cancel out the 7.0% loan). The 7.4% received more than covers the 7.0% paid, netting +0.40%. Then Rich only owes HIBOR (the floating leg of the swap).

Rich Bank's Math

Item	Fixed	Floating

Green Corporation's Math

Item	Fixed	Floating

Savings Comparison

Effective rate WITH swap vs WITHOUT swap

4 IRS = A Series of Forward Rate Agreements

Each payment period is just a bet on where rates will be.

Think of it this way: A 5-year swap with quarterly payments has 20 payment dates. Each payment date is essentially a separate Forward Rate Agreement (FRA) — a bet on what the floating rate will be on that specific date, compared to the fixed rate you locked in.

Interactive: 5-Year Swap Timeline

Click any period to see details. Use the scenario buttons to see different rate paths.

Fixed Swap Rate 5.0%

Total P&L for Fixed Payer:

Periods in profit: Periods in loss:

Why "Series of Forwards"?

A Forward Rate Agreement (FRA) is a one-time bet: "I'll pay you 5% fixed, you pay me whatever HIBOR is on date X." One period, one settlement.

An Interest Rate Swap is just doing that SAME bet for EVERY period over the life of the swap — say 20 quarters over 5 years.

So a swap is literally: FRA(period 1) + FRA(period 2) + FRA(period 3) + ... + FRA(period 20). A bundle of forwards.

5 Paying Fixed = Betting Rates Go Up

Why would you lock in a fixed payment? Because you think floating will cost you MORE.

Analogy: It's like buying an all-you-can-eat buffet pass for $30. If meals normally cost $10 each, you need to eat 4+ meals to "win." You're betting you'll eat a LOT (rates go up a LOT). If you only eat 2 meals, the buffet wins. Paying fixed = buying the buffet pass. You win when the "price per meal" (floating rate) goes up.

Rate Scenario Simulator

You're paying 5% fixed. Drag the slider to see what happens when floating rates change:

Your Fixed Rate (locked in) 5.0%

Actual Floating Rate (what happened) 5.0%

5.0%

You Pay (Fixed)

5.0%

You Receive (Float)

0.0%

Your Net P&L

If You PAY Fixed

Breakeven

Float = Fixed, no net payment

If You RECEIVE Fixed

Breakeven

Float = Fixed, no net payment

The Payoff Chart

This shows the P&L for the fixed-rate payer across all possible floating rates:

Above zero = you profit (rates rose above your fixed rate) | Below zero = you lose (rates stayed low)

Summary: Who Bets What?

Position	Betting On	Wins When	Loses When
Pay Fixed / Receive Float	Rates go UP	Floating > Fixed (you receive more than you pay)	Floating < Fixed (you pay more than you receive)
Pay Float / Receive Fixed	Rates go DOWN or stay low	Floating < Fixed (you pay less than you receive)	Floating > Fixed (you pay more than you receive)

6 Key Takeaways

Everything you need to remember, in 30 seconds.

A swap exchanges payment streams. Most commonly, fixed interest for floating interest on the same notional amount.

Only the NET difference is exchanged. If fixed = 5% and floating = 6%, the fixed payer receives 1% of the notional.

Comparative advantage creates mutual savings. Parties with different credit qualities can both reduce borrowing costs.

An IRS is just a bundle of Forward Rate Agreements. Each payment date is a separate FRA — a bet on what the floating rate will be.

Paying fixed = betting rates rise. You win when floating exceeds your locked-in fixed rate. The swap compensates you when rates go up.

"Plain vanilla" swaps are the most common type: simply swapping fixed for floating (or vice versa). They're called "plain vanilla" because they're the most basic, standard flavor — no exotic toppings!