Mortgage banking and its ALM interaction

Mortgage Banking and Its ALM Interaction

Mortgage banking is intimately connected to ALM. Mortgages are long-term, fixed-rate assets that consume balance sheet capacity, create interest rate risk, and can be securitized to manage capital and liquidity.

The Mortgage Balance Sheet Impact

Mortgages create multiple ALM challenges:

1. Duration risk: 30-year mortgages have high duration. When rates rise, they lose value. When rates fall, borrowers prepay.
2. Funding mismatch: Mortgages are long-term; deposits are short-term. Maturity mismatch creates EVE risk.
3. Capital consumption: Mortgages require capital. Growing the mortgage book consumes capital that could be used elsewhere.
4. Liquidity: Mortgages are illiquid. They can't be sold quickly without a secondary market (or securitization).

Mortgage Securitization as an ALM Tool

Securitization removes mortgages from the balance sheet, freeing up:

• Funding capacity: No longer consuming deposits/wholesale debt


• Capital: Lower risk-weighted assets


• Interest rate risk: Removing long-duration assets

Banks typically securitize 50-70% of mortgage production, keeping 30-50% on balance sheet. The economics:

Mortgage held on balance sheet:

• Rate to customer: 6.50%


• Funding cost: 4.00% (FTP)


• Credit cost: 0.30%


• Operating cost: 1.50%


• Profit: 0.70%


• Capital consumption: 4%

Mortgage securitized:

• Rate to customer: 6.50%


• Securitization cost: 0.25% (servicing, guarantee, etc.)


• Credit cost: 0.30%


• Operating cost: 1.50%


• Profit: 4.45%

But: Bank no longer owns the mortgage; gets paid a fee

• Effective profit to bank: ~0.45% (lower because the origination fee and servicing income don't cover the spread you'd earn by holding)


• Capital consumption: ~0.5% (much lower)

Securitization is profitable but less profitable than holding. Banks securitize primarily for capital efficiency and balance sheet capacity, not to maximize spread profit.

Real Example: Mortgage Portfolio Management

Bank has:

• $25B in mortgages (40% of assets)


• $15B in other loans (24%)


• $12B in securities (19%)


• Other assets: $8B (13%)

Mortgage origination request: $2B per quarter

ALM analysis:

• Current EVE sensitivity: -10% of capital under -200 scenario


• If we add $2B mortgages to balance sheet:

- New EVE sensitivity: -12.5% (exceeds 12% limit)

• Options:

1. Cap originations at $800M (don't securitize), retain $200M (securitize 75%)
2. Securitize 70% of $2B, retain $600M on balance sheet (EVE sensitivity: -11.2%, within limit)
3. Use interest rate swaps to hedge half the mortgages (cost: 30 bps, but reduces EVE sensitivity to -11.5%)

Most banks choose option 2: securitize a portion to manage balance sheet constraints.

Takeaway

Mortgage banking and ALM are inseparable. Mortgages consume balance sheet capacity and create duration risk. Securitization is the primary tool for managing this risk while still growing mortgage business.

Mortgage Banking and Its ALM Integration: The Origination-Securitization Tension

Mortgage banking is often the largest consumer lending business at regional and mid-size banks. It's also one of the most operationally complex, capital-intensive, and tightly constrained by ALM policy. Understanding how mortgage banking works, why it matters to ALM, and where the tensions live is essential for any ALM manager working with mortgage originators.

The Origination-Securitization Economics

When a mortgage originator closes a loan, the bank doesn't inherently keep it on the balance sheet. Instead, it's immediately securitized or sold to an investor. This happens because mortgage banking economics are fundamentally about gain-on-sale and servicing income, not long-term portfolio accumulation.

Here's the mechanics. A customer applies for a $400,000 mortgage at a 6.50% rate. The bank commits to funding this loan by warehousing it temporarily, hedging the interest rate risk, and then quickly selling it to an investor. The investor, meanwhile, is willing to buy the mortgage at a 6.25% yield (the investor takes the credit and duration risk). The spread—6.50% minus 6.25%, or 25 basis points on $400,000—generates $1,000 in gain on sale.

Across a $1 billion mortgage origination volume in a year, a 25 basis point gain-on-sale spread creates $2.5 million in net origination income. This is upfront, immediate profit. The bank also retains servicing rights on the loan, generating ~25 basis points annually ($2.5 million per year) for managing escrow, insurance, tax administration, and borrower communications.

Now consider the alternative: The bank retains mortgages on balance sheet rather than selling. There's no gain-on-sale (you didn't sell), but you earn the full 6.50% spread on your retained mortgage portfolio. Minus deposit funding costs (say 2.50%), credit losses (say 0.25%), and operations overhead (say 0.50%), you're earning around 3.25% net spread. On a $1 billion portfolio, that's $32.5 million annually. Plus servicing income ($2.5 million). Total: $35 million.

Superficially, retaining mortgages seems better ($35M vs. $2.5M). But the capital math changes everything. A $1 billion mortgage portfolio requires substantial capital: ~$100 million in regulatory capital (assuming 10% capital ratio). That capital could instead be deployed in higher-return businesses (card lending at 15%+ spread, commercial lending at 3%+) or returned to shareholders. JPMorgan and Bank of America realize this and securitize most mortgages aggressively.

Warehouse Lending and Pipeline Hedging

Between origination and securitization, mortgages sit on the bank's balance sheet in a "warehouse" facility. The warehouse is funded at short-term rates (typically overnight SOFR + 25-50 bps) and holds mortgages for 30-60 days until they're packaged for securitization.

This creates a funding mismatch: You're funding long-term assets (mortgages) with short-term money. If rates rise 100 basis points before securitization, the mortgages you originated at 6.50% are now less valuable (the market trades them at 7.50%). You've created an unrealized loss on the warehouse.

This is where pipeline hedging enters. When mortgage originators lock in customer rates, the ALM/treasury team immediately hedges the exposure. If $100 million of mortgages have been locked at 6.50%, the hedge is typically a short position in mortgage-backed securities or a long position in Treasury futures (short duration exposure). The hedge protects the bank: If rates rise, the MBS short position gains, offsetting the mortgage decline.

In practice, this is messy. The mortgages and the hedge aren't perfect matches. Mortgages have prepayment risk (if rates fall, customers refinance and you lose the yield spread). MBS shorts have different mechanics. Plus, not all locked mortgages close (applications fall through, customers withdraw). So the hedge is never perfect. The ALM team runs daily "Greeks" (duration, gamma, vega exposure) to monitor hedge effectiveness.

A real example: Your mortgage team locks $250 million of mortgages at 6.50% on Tuesday. Your ALM team immediately shorts $250 million of MBS (or uses Treasury futures) to hedge. Wednesday, Fed Chair Kaplan speaks hawkishly and rates spike 50 basis points. Mortgage values fall ~$625,000 (duration impact). Your MBS short gains ~$625,000. The hedge worked. Costs are minimal.

But what if applications don't close? You have $200 million of mortgages that close, $50 million that withdraw. You're now 50% overhedged. You have a short position in MBS that you no longer need. You cover the position, crystallizing gains or losses depending on rate moves. This is a normal ALM operation but requires daily discipline.

Mortgage Servicing Rights and Revaluation

When you originate and securitize a mortgage, you typically retain the servicing right (MSR). An MSR is a contractual right to collect principal, interest, and escrow payments, take a small fee, and remit the difference to investors. MSRs are valuable but volatile assets.

MSR valuation is complex. An MSR's value depends on:

Prepayment assumptions. If rates fall, borrowers refinance faster, shortening the MSR's income stream. The MSR becomes less valuable. If rates rise, prepayments slow, lengthening the income stream. The MSR becomes more valuable.

Servicing costs. If inflation raises labor costs, the net servicing spread (the fee you collect minus costs) compresses. MSRs become less valuable.

Portfolio composition. MSRs on non-conforming loans (lower credit quality, higher rates) have lower prepayment sensitivity. They're more valuable than MSRs on prime mortgages (which refinance aggressively when rates fall).

Banks carrying MSRs on their balance sheet must revalue them quarterly based on rate expectations, prepayment models, and cost assumptions. A significant rate drop (300 basis points) might cause MSRs to lose 10-20% of value. This can be hundreds of millions of dollars for a large mortgage servicer.

Wells Fargo, a major servicer, reported MSR declines of billions of dollars in periods of falling rates (e.g., 2020-2021). The economic reality: Your servicing rights decline when rates fall, which is precisely when mortgage demand surges. This creates a natural hedge for mortgage originators (you lose on MSRs but gain on origination volumes), but ALM must manage the balance sheet impact.

Duration and Prepayment Sensitivity

For mortgages retained on balance sheet, ALM models prepayment behavior using S-curve prepayment models. These models predict that prepayment speeds increase nonlinearly as rates fall below the mortgage's coupon.

Example: You hold $500 million of mortgages originated at 6.00% rates. Current rates are 6.50% (rates have risen). Prepayment speeds are slow (~6% CPR, conditional prepayment rate). The mortgages' effective duration is 6.5 years.

Rates then fall to 5.50%. Borrowers aggressively refinance. CPR jumps to 45%. The mortgages' effective duration collapses to 2.0 years. You now have much shorter-duration assets, and your overall portfolio duration has shortened. If you were hedged at 5.5-year duration, you're now over-hedged and your duration risk has flipped.

Mortgage ALM requires continuous monitoring of CPR assumptions and effective duration calculations. Sophistical banks run daily duration and prepayment sensitivity reports. A 1% change in mortgage rates might change your portfolio duration by 0.5 years. You need to know this immediately.

Mortgage Banking and Origination Volume Cycles

Mortgage originations are cyclical and leverage-dependent. When rates fall, origination volumes surge. Your mortgage team closes 10x their normal volume, originating $5 billion of mortgages in 60 days instead of a year. This creates operational strain: hiring, systems, quality control all degrade. It also creates ALM strain: Your warehouse facility swells, your pipeline hedge becomes massive, your securitization pace accelerates.

Conversely, when rates rise sharply, origination volumes collapse. Your mortgage team is idle, your fixed costs (salaries, systems) continue, and you're losing money on the business.

ALM's role is to absorb these swings without breaking. You need:

• Warehouse capacity that flexes with volume (done via credit facilities that can expand/contract)
• Pipeline hedges that scale with origination locks
• Securitization capability to move mortgages off balance sheet quickly
• Capital to absorb losses if something breaks (e.g., a major lender fails, closing its mortgage business, and mortgages build up in your warehouse)

The Practical Seat: ALM Manager Negotiating with Mortgage Business

Here's what this means in the seat: When your mortgage VP comes to ALCO saying "We want to grow originations from $2B to $4B annually," ALM must evaluate:

1. Warehouse capacity: Do we have credit facilities to warehouse $150M of mortgages (typical for 60-day cycle)? Do we need to expand?
2. Hedge costs: What's the daily cost to hedge $4B of locked mortgages? At current volatility and rates, maybe 15 basis points. That's $600K annually. Is it worth it for the gain-on-sale income?
3. Securitization capability: Can we securitize $4B annually? Do we use internal securitization or sell to Fannie Mae/Freddie Mac? Each has capital implications.
4. Capital and returns: After all costs, does $4B of originations add economic value or just eat capital?

If the mortgage business can't clear a 1.50% all-in net return (gain on sale, servicing, minus hedging costs and capital cost), it's not worth growing. This is the tension between business line ambition and ALM discipline.

Takeaway: Mortgage Banking as ALM Constraint

Mortgage banking is high-volume, low-margin, operationally complex, and tightly constrained by ALM. The best ALM managers understand the origination-securitization cycle, monitor duration and prepayment risk relentlessly, and set clear return hurdles for mortgage growth. This prevents mortgage banking from becoming an ALM tail wagging the balance sheet dog.