Current yield measures cash income as a fraction of price. Internal rate of return (IRR) measures the total growth rate of every dollar invested, accounting for the timing of each cash flow, reinvestment, and the return of principal. For private lenders evaluating a note purchase, IRR is the more complete metric — but yield tells you what hits your account each period.

Key Takeaways

• Current yield divides periodic income by the asset’s price; it ignores timing, principal recovery, and the cost of early payoff.
• IRR solves for the single discount rate that makes the present value of all cash flows equal to zero — it captures every dollar and when it arrives.
• When a borrower prepays, yield-to-maturity calculations break down; IRR automatically absorbs the prepayment into its cash-flow sequence.
• Yield-to-maturity assumes reinvestment at the same coupon rate; IRR makes no reinvestment assumption beyond what the cash flows show.
• Use yield for quick income screening; use IRR for cross-note comparison and portfolio performance attribution.

What Yield Actually Measures

Private lenders encounter two yield calculations in practice. Current yield divides the note’s annual interest income by the current purchase price. A note paying an annual coupon of C dollars purchased for P dollars carries a current yield of C ÷ P. That number answers one question only: what fraction of today’s invested capital returns as income each year if price and coupon hold constant.

Yield-to-maturity (YTM) adds principal recovery to the picture. It is the internal rate that, when applied to the note’s remaining coupon payments plus the balloon or final payoff, produces a present value equal to today’s purchase price. A note bought at a discount to face value produces a YTM above the coupon rate because the investor also earns the discount upon payoff.

Both measures treat the note as if it runs uninterrupted to a fixed maturity date. That assumption works for agency paper. It breaks on private notes, where portfolio performance is routinely shaped by early payoffs, delinquencies, and modifications. When any of those events occurs, the cash-flow sequence the yield calculation assumed no longer exists — and the yield figure becomes inaccurate without recalculation.

Yield is still useful as a quick filter. If a note’s current yield falls below your minimum income threshold before any adjustment for risk or credit quality, the analysis stops there. But passing a yield screen is not the same as understanding the investment’s total economics. For that, you need IRR.

What IRR Actually Measures

Internal rate of return (IRR) solves for the discount rate at which the net present value of all cash flows — outflows and inflows — equals zero. In plain terms: if you invest P dollars today and receive cash flows CF₁, CF₂ … CFₙ at defined points in time, IRR is the annualized growth rate that explains every dollar of return across the entire holding period.

IRR requires three inputs: the initial outlay, every subsequent cash flow with its timing, and a final terminal value (the payoff, sale price, or balloon receipt). Nothing is assumed about what happens to cash received along the way — the calculation uses the actual cash flows as stated. That makes IRR a faithful reflection of what the investment did, not what it would do under ideal reinvestment conditions.

For a private lender using a consistent performance framework, IRR is the metric that translates across unlike notes: a fully amortizing residential note, a short-term bridge with a balloon, and a partially deferred interest note all produce IRR figures on the same scale, making direct comparison possible.

The practical limitation is data dependency. IRR is only as accurate as the cash-flow record feeding it. A servicer who tracks every principal receipt, interest posting, escrow disbursement, and late charge in a structured ledger gives you clean IRR inputs. A self-serviced portfolio where payments are tracked in a spreadsheet introduces errors that compound across the calculation period.

Yield vs. IRR: Side-by-Side Comparison

How Prepayment Changes Each Metric

Prepayment is the most common disruption to a private note’s expected cash-flow sequence. A borrower who refinances or sells the property returns the remaining principal balance before the maturity date assumed in the yield calculation.

For yield-to-maturity, prepayment invalidates the calculation. YTM was solved against a specific maturity — when that maturity disappears, the YTM figure is no longer meaningful. A lender who bought a discount note counting on holding to maturity to capture the spread loses some of that gain when the note pays off early. Recalculating YTM requires a new assumed maturity or a recognition that no future YTM is possible — only realized yield from closing date to payoff date.

IRR handles prepayment cleanly. The actual payoff amount and the actual payoff date replace the originally modeled terminal cash flow. The recalculated IRR reflects the true economics of the hold: the income received, the timing of that income, and the final principal recovery — all at their real dates. If the note paid off early, the investor recovered capital sooner, which in most scenarios improves IRR relative to a longer hold at the same coupon rate.

This distinction matters for portfolio-level performance tracking. A portfolio of private notes will experience prepayments at irregular intervals. An IRR-based reporting framework absorbs each one without requiring manual restatement of every affected note’s yield figure. A yield-based framework requires constant recalibration as the assumed maturities of prepaid notes are retired.

Professional loan servicing produces the timestamped payment records that make post-prepayment IRR calculation accurate. Without a servicer maintaining a complete payment ledger, the lender is estimating — and IRR built on estimates is not a reliable performance metric.

Expert Take: Why IRR Is the Metric We Build Reporting Around

When to Use Yield and When to Use IRR

Yield and IRR are not competing tools — they answer different questions. Using the right metric for the right decision eliminates a common source of investor confusion.

Use current yield when: You are screening a note for income sufficiency. Before running a full IRR model, confirm the note’s periodic cash flows meet your minimum distribution requirement. Current yield answers that question quickly, without requiring a full cash-flow schedule.

Use YTM when: The note carries a significant discount or premium to face value and you want to understand the total return assuming no prepayment. YTM is also useful for comparing a discounted note purchase against an alternative investment with a known maturity and fixed coupon — both can be expressed in YTM terms on the same basis.

Use IRR when: You are making an acquisition decision across unlike note structures. When your choice set includes a balloon note, a fully amortizing note, and a partial purchase at a discount, IRR places all three on a single comparable scale. IRR is also the correct metric for after-the-fact portfolio attribution — what did each note actually return, given what the borrower actually did.

The dividing line: yield-based metrics are forward-looking projections under assumed conditions. IRR is both a forward-looking projection (using modeled cash flows at acquisition) and a backward-looking fact (using actual cash flows after the note matures or pays off). That dual nature makes IRR the standard for private lending portfolio performance measurement.

Frequently Asked Questions

Can a note have a high yield but a low IRR?

Yes. A note purchased at a significant premium to face value produces a high current yield from the coupon but a lower IRR because the investor absorbs the premium loss upon payoff. The current yield figure ignores that principal erosion; IRR captures it as a negative cash flow at the terminal date. This is why a yield screen alone is an incomplete filter for note acquisitions where the purchase price departs from face value.

Does IRR assume I reinvest my monthly payments?

No. IRR makes no assumption about what happens to cash received between payments. The calculation treats each cash flow as occurring at its stated date and solves for the rate that equates the full series to the initial outlay. The reinvestment assumption is embedded in YTM — not in IRR — which is one reason IRR is a more conservative and realistic metric for private lenders who do not immediately redeploy each month’s payment at the same rate.

How does a delinquency affect my IRR?

A delinquency delays cash flows that the IRR model assumed would arrive on schedule. When those cash flows arrive late — or arrive partially through a modification — the IRR for the note decreases relative to the original model, because the timing of receipt matters in the present-value calculation. A late payment is worth less than an on-time payment of the same amount. Accurate IRR tracking requires your servicer to record the actual payment dates, not the scheduled dates.

Which metric do secondary market note buyers use to price notes?

Secondary market buyers use IRR as their primary pricing metric. A buyer modeling the acquisition constructs a cash-flow schedule from the remaining loan balance, remaining term, contractual payment amount, and any known credit history, then solves for the purchase price that produces a target IRR. Yield-to-maturity is used as a cross-check when the note carries a significant discount. Understanding IRR mechanics gives note sellers a clearer basis for negotiating price.

Does my servicer need to calculate IRR for me?

Your servicer produces the inputs IRR requires — the verified payment ledger, the payoff date, the exact principal balance at each point in time. The IRR calculation itself runs in any financial calculator or spreadsheet. What distinguishes professional servicing is the accuracy and completeness of the data that feeds the calculation. A licensed note servicer maintains a transaction-level ledger that supports audit-grade IRR computation; a self-managed spreadsheet does not.

Sources & Further Reading

• Internal Rate of Return (IRR) — Investopedia — Foundational definition and calculation methodology
• 26 U.S.C. §1272 — Original-Issue-Discount Rules — Cornell LII; governs accrual and taxation of discount instruments including private notes
• 12 CFR Part 1026 (Regulation Z) — CFPB; disclosure and calculation standards for credit instruments including APR, which uses an IRR-equivalent methodology
• Mortgage Bankers Association — Industry data including the Servicing Operations Study of the Future (SOSF), source of published per-loan servicing cost benchmarks