Why Mortgage Rates Fluctuate

One day your quoted mortgage rate is 4.8%. A week later it is 5.1%. Nothing in your application changed. You did not switch lenders. Your credit score stayed the same. Yet the rate you qualify for jumped enough to add hundreds of dollars to your monthly payment. What is happening?

Mortgage rates seem to move randomly, but they follow predictable patterns once you understand what drives them. Rates do not come out of thin air. They are the end result of a chain of economic forces, policy decisions, and market dynamics. Understanding this chain helps you make smarter decisions about when to lock in and whether to choose fixed or variable.

The Two Types of Rates Follow Different Rules

Before diving into what moves rates, you need to understand that fixed and variable rates are driven by completely different factors. They move independently of each other.

Variable rates track the Bank of Canada overnight rate. When the Bank of Canada raises or lowers its policy rate, variable mortgage rates follow within days. This is a direct, mechanical relationship.

Fixed rates track government bond yields. Specifically, the 5-year Government of Canada bond yield is the benchmark for 5-year fixed mortgage rates. This relationship is indirect but highly correlated.

This distinction matters because fixed and variable rates can move in opposite directions. Fixed rates might rise while variable rates fall, or vice versa. Choosing between them requires understanding both drivers.

Variable Rates: The Bank of Canada Connection

The Bank of Canada sets the overnight rate eight times per year. This is the rate banks charge each other for overnight loans. It serves as the anchor for the entire Canadian lending system.

When the Bank of Canada raises the overnight rate, banks immediately face higher borrowing costs. They pass this cost to consumers through higher prime rates, which variable mortgages are priced from. A 0.25% increase in the overnight rate typically translates to a 0.25% increase in variable mortgage rates within one to three business days.

The Bank of Canada adjusts rates based on its mandate: keep inflation at 2% while supporting maximum sustainable employment. When inflation runs hot, the Bank raises rates to cool the economy. When inflation is low and growth stalls, the Bank cuts rates to stimulate borrowing and spending.

The Bank of Canada website publishes the schedule of rate announcements months in advance. Variable rate borrowers can mark these dates on their calendars. If you are considering variable, pay attention to these announcements.

Fixed Rates: The Bond Market Connection

Fixed mortgage rates follow the 5-year Government of Canada bond yield, plus a spread. This spread typically ranges from 1% to 2%, depending on market conditions and lender competition.

Bond yields move based on investor expectations about future inflation and economic growth. When investors expect inflation to rise, they demand higher yields to compensate for the eroding value of future payments. Bond prices fall, yields rise, and fixed mortgage rates follow.

When investors expect economic slowdown or recession, they flock to the safety of government bonds. Bond prices rise, yields fall, and fixed mortgage rates typically drop.

This is why fixed rates often move before the Bank of Canada changes its policy rate. Bond markets are forward-looking. They price in expected rate changes months before they happen.

The Lender Spread: Why Posted Rates Differ

Even when bond yields are stable, mortgage rates vary between lenders. This spread reflects several factors.

Funding costs: Different lenders access capital differently. Banks fund mortgages through deposits and wholesale markets. Credit unions rely on member deposits. Alternative lenders use private capital. Each funding source has different costs that get passed to borrowers.

Risk appetite: Lenders adjust rates based on how aggressively they want to grow their mortgage portfolio. A lender trying to expand market share offers lower rates. A lender at capacity might raise rates to slow applications.

Product mix: Some lenders specialize in insured mortgages and offer better rates for high-ratio loans. Others focus on conventional mortgages for established homeowners. The same lender might have different rates for different products.

This spread explains why shopping around matters. The bond yield might be the same for everyone, but the spread varies significantly.

Global Forces: Why Canadian Rates Follow the World

Canada does not exist in a vacuum. Our rates are influenced by global economic forces, particularly the United States.

When the U.S. Federal Reserve raises rates, the Bank of Canada often follows to maintain the value of the Canadian dollar. If Canadian rates lag too far behind U.S. rates, capital flows to the United States seeking better returns, weakening the loonie and increasing import costs.

Global events also matter. Financial crises, geopolitical tensions, and pandemics create uncertainty that drives investors to safe assets like government bonds. This flight to safety can push Canadian bond yields lower even when domestic conditions suggest rates should rise.

Why Your Rate Quote Changes Daily

If you have ever been quoted a mortgage rate that was different the next day, you experienced the reality of rate volatility. Lenders update their rates constantly based on:

• Bond yield movements: Bond traders work in real-time. Lenders adjust fixed rates throughout the day as yields move.
• Application volume: When a lender receives too many applications, they might raise rates to slow the flow. When volume is low, they cut rates to attract business.
• Competitive positioning: Lenders monitor each other. If a major bank cuts rates, competitors often follow within hours.
• Hedging costs: Lenders hedge their rate commitments. When volatility increases, hedging becomes more expensive, and rates rise to compensate.

Most lenders offer rate holds of 90 to 120 days. Once you lock in, your rate is protected even if market rates rise. But if rates fall, you typically get the lower rate at funding. This asymmetry makes rate holds valuable during volatile periods.

What This Means for Your Mortgage Decision

Understanding rate drivers helps you think about mortgage timing and product selection.

If you believe inflation will remain high and the Bank of Canada will keep raising rates, locking into a fixed rate makes sense. You protect yourself from further increases.

If you believe the economy is slowing and rates will fall, a variable rate might save you money as the Bank of Canada eventually cuts.

But here is the truth nobody wants to hear: predicting rate movements is extremely difficult. Professional economists get it wrong constantly. Bond markets price in expectations that often do not materialize. The Bank of Canada surprises markets with unexpected decisions.

Your mortgage decision should not be based on where you think rates are going. It should be based on your financial situation, your risk tolerance, and your ability to handle payment uncertainty. Understanding how rates work helps you make that decision intelligently, not predictively.

Use our mortgage calculator to see how rate changes affect your payments. Explore more in our mortgage basics section. Contact Browne Mortgage to discuss current rates and whether fixed or variable makes sense for your situation.