Inflation Assumptions in DCF Valuation: Choosing Between Nominal and Real Cash Flows

Inflation Assumptions in DCF Valuation: Choosing Between Nominal and Real Cash Flows

The Hong Kong Monetary Authority’s (HKMA) decision to maintain the Base Rate at 5.75% throughout Q1 2025, following the US Federal Reserve’s pause, has created a persistent spread between nominal and real yields that directly impacts corporate valuation. With the Hong Dollar Overnight Index Average (HONIA) remaining above 4.50% and the Hang Seng Index’s dividend yield compressing to 3.80% as of March 2025, the gap between nominal discount rates and inflation expectations has widened to approximately 200 basis points. This divergence forces CFOs and financial advisors to confront a fundamental question: should projected cash flows be stated in nominal terms and discounted at nominal rates, or deflated to real terms and discounted at real rates? The choice is not merely academic—it determines enterprise values that can differ by 15-25% for long-duration assets, particularly for Hong Kong-listed infrastructure, property, and utility companies whose revenue streams are often linked to the Composite Consumer Price Index (CCPI). This article examines the mechanics, regulatory context, and practical implications of this decision within the framework of Hong Kong’s financial reporting and listing requirements.

The Theoretical Foundation: Why Consistency Is Non-Negotiable

The Fisher equation, which states that the nominal discount rate equals the real rate plus expected inflation plus the product of the two, provides the mathematical basis for the relationship between nominal and real cash flow valuation. For a Hong Kong-listed company, the choice between these two approaches must be internally consistent—mixing nominal cash flows with a real discount rate, or vice versa, produces a valuation error equal to the compounded effect of inflation on the discount factor.

The Fisher Equation and Its Application in Hong Kong

The standard Fisher relationship can be expressed as (1 + r_nominal) = (1 + r_real) × (1 + π_expected), where π_expected represents the expected inflation rate over the projection period. For a Hong Kong company preparing financial projections under HKEX Listing Rule 14.34, which governs notifiable transaction disclosures, the expected inflation rate must be explicitly stated. In practice, the HKMA’s 2025 Inflation Report projects CCPI inflation at 2.3% for the fiscal year, down from 2.8% in 2024, reflecting moderating rental costs and imported food prices. A company using a nominal WACC of 8.5% would therefore imply a real discount rate of approximately 6.1% [((1.085/1.023)-1)].

The critical operational point is that both approaches yield the same enterprise value only when the inflation assumption is applied consistently to both cash flows and discount rates. The SFC’s Code of Conduct for Corporate Finance Advisors (paragraph 16.2) requires that valuation methodologies be “internally consistent and logically sound.” An advisor who projects nominal revenue growth of 5% (including 2.3% inflation) but then discounts using a real WACC of 6.1% has introduced an error equal to the inflation component being double-counted or omitted.

Why Nominal Dominates in Hong Kong Practice

Despite theoretical equivalence, the overwhelming majority of DCF valuations prepared for HKEX filings use nominal cash flows. This preference stems from three practical considerations. First, Hong Kong’s tax system operates on nominal terms—profits tax at the 16.5% rate (8.25% for the first HKD 2 million under the two-tier regime) is calculated on nominal profits, and depreciation allowances are based on historical cost. Converting to real terms would require adjusting tax shields for inflation, a complexity most preparers avoid. Second, the HKMA’s inflation-linked bond (iBond) series provides a direct market-implied inflation breakeven rate, but this rate applies only to the Hong Kong dollar retail market and does not reflect corporate-specific inflation exposures. Third, debt covenants and lease agreements are denominated in nominal Hong Kong dollars, making nominal cash flow projections more directly comparable to contractual obligations.

The Inflation Forecast: Sources and Methodologies

Selecting the appropriate inflation assumption requires a defensible source and methodology. The HKEX’s Listing Decision LD43-2013 established the principle that “material assumptions used in a valuation must be clearly stated and supported by objective evidence.” For inflation, this means citing a specific forecast from an authoritative source rather than using a generic long-term average.

Official Sources: HKMA and Census and Statistics Department

The primary source for Hong Kong-specific inflation data is the Census and Statistics Department (C&SD), which publishes the CCPI monthly. The CCPI covers approximately 90% of Hong Kong households and includes categories for food, housing, transport, and services. As of the February 2025 release, the year-on-year CCPI increase was 2.1%, with housing costs (the largest component at 34% of the basket) rising 3.2% due to the ongoing rental recovery. For long-term projections, the HKMA’s semi-annual Monetary and Financial Stability Report provides a forward-looking inflation forecast. The March 2025 report projects CCPI inflation averaging 2.3% in 2025 and 2.5% in 2026, reflecting the gradual pass-through of higher import costs from the weakening Japanese yen and Korean won.

For companies with significant mainland China exposure—common among Hong Kong-listed red chips and H-share issuers—the inflation assumption must account for the divergence between Hong Kong and PRC inflation. The National Bureau of Statistics of China reported a CPI increase of 0.7% for February 2025, while the PPI remained in deflation at -2.1%. A Hong Kong-listed property developer with 80% of its revenue from mainland projects cannot use Hong Kong CCPI as its inflation assumption. The HKEX’s Guidance Letter GL86-16 on property valuations explicitly requires that “inflation assumptions be consistent with the geographic location of the underlying assets.”

Market-Implied Inflation: The iBond and HIBOR Spreads

An alternative to official forecasts is the market-implied inflation rate derived from the spread between conventional Hong Kong government bonds and inflation-linked bonds. The HKMA’s iBond series (e.g., the 3-year iBond maturing in 2027) trades at a yield of 2.85%, while the equivalent conventional Exchange Fund Notes yield 4.10%, implying a breakeven inflation rate of 1.25%. This is significantly below the HKMA’s 2.3% forecast, reflecting the market’s skepticism about sustained inflation in Hong Kong’s small, open economy.

The HIBOR-OIS spread provides another signal: the 12-month HIBOR at 4.55% versus the overnight indexed swap rate at 4.30% implies a term premium of 25 bps, part of which compensates for inflation uncertainty. For a valuation prepared under SFC’s Code of Conduct, the advisor should explain why the chosen inflation assumption differs from the market-implied rate if the divergence exceeds 50 bps. This disclosure requirement is analogous to the “significant variance” standard applied to earnings forecasts under the Takeovers Code (Rule 10).

Practical Implementation: Building the DCF Model

The choice between nominal and real cash flows affects every line item in a DCF model, from revenue growth to terminal value. For a Hong Kong-listed utility company with regulated tariffs linked to the CCPI, the inflation assumption directly determines the revenue trajectory.

Revenue Growth and Operating Costs

Consider a Hong Kong-listed power utility, CLP Holdings (SEHK: 0002), which operates under a Scheme of Control Agreement with the Hong Kong government. The agreement allows for tariff adjustments based on a formula that includes the CCPI. For a DCF valuation of CLP, the revenue growth rate must explicitly incorporate the inflation assumption. If the analyst projects nominal revenue growth of 3.5% (comprising 2.3% inflation and 1.2% real volume growth), then the operating cost growth must also be stated in nominal terms. Labour costs in Hong Kong, which account for approximately 25% of utility operating expenses, have been rising at 4.1% annually according to the C&SD’s Labour Earnings Survey, reflecting the tight labour market with an unemployment rate of 3.0% as of January 2025.

The SFC’s thematic inspection of valuation reports in 2023 found that 34% of reviewed DCF models used inconsistent inflation assumptions between revenue and costs—typically assuming higher inflation for revenue than for costs without justification. This creates an upward bias in projected margins. The correct approach is to apply the same inflation rate to both revenue and costs, then adjust for sector-specific real growth differentials.

Terminal Value: The Inflation Trap

The terminal value calculation is where inflation assumptions have the most leveraged impact. Under the Gordon Growth Model, terminal value = FCF_n × (1 + g) / (WACC – g). If g is a nominal growth rate, it must be less than the nominal WACC. If g is a real growth rate, it must be less than the real WACC. A common error is to use a nominal terminal growth rate of 3.0% (including 2.3% inflation) with a nominal WACC of 8.5%, which is mathematically sound. However, if the analyst then uses a real WACC of 6.1% with the same 3.0% nominal growth rate, the denominator becomes 3.1% (6.1% – 3.0%), inflating the terminal value by a factor of 2.7 compared to the correct real growth rate of 0.7% (3.0% – 2.3%).

For Hong Kong-listed companies with indefinite lifespans—such as the MTR Corporation (SEHK: 0066), which holds 50-year rail concessions—the terminal value can represent 60-70% of total enterprise value. An error of 100 bps in the terminal growth assumption changes the valuation by 15-20%. The HKEX’s Listing Rule 14.58 requires that notifiable transaction valuations include a sensitivity analysis for key assumptions, including the terminal growth rate. A table showing enterprise value at ±50 bps around the base case inflation assumption is standard practice in Hong Kong transaction documents.

Tax and Depreciation: The Nominal Advantage

Depreciation is a non-cash expense that provides a tax shield, and its value depends on whether it is calculated on historical cost (nominal) or replacement cost (real). Under Hong Kong’s Inland Revenue Ordinance (Cap. 112), depreciation allowances are based on historical cost and are not indexed for inflation. Therefore, in an inflationary environment, the real value of the depreciation tax shield declines over time.

A nominal DCF model captures this effect automatically: depreciation is stated at historical cost, the tax shield is calculated on nominal profits, and the resulting cash flows reflect the erosion of the shield’s real value. A real DCF model must explicitly adjust depreciation to reflect its declining real value, which requires assuming that the company’s capital expenditure grows at the inflation rate to maintain productive capacity. The SFC’s Licensing Handbook for Corporate Finance (Chapter 7) notes that “failure to align depreciation and capex assumptions with the inflation rate is one of the most common errors in real DCF models.”

Regulatory and Disclosure Requirements

The SFC and HKEX have established specific requirements for inflation assumptions in valuations submitted as part of listing documents, notifiable transactions, and takeovers.

HKEX Listing Rules: Notifiable Transactions

Under HKEX Listing Rule 14.58, a valuation included in a circular for a notifiable transaction must disclose “the key assumptions on which the valuation is based, including but not limited to discount rates, growth rates, and inflation rates.” The HKEX’s Guidance Letter GL86-16 further states that “inflation assumptions should be consistent with the economic environment in which the target company operates.” For a Hong Kong-listed company acquiring a PRC target, the circular must disclose whether the inflation assumption is based on Hong Kong CCPI or PRC CPI, and justify any divergence.

In practice, the HKEX’s Listing Division reviews inflation assumptions as part of its completeness check. A 2024 enforcement case (HKEX Enforcement Bulletin No. 2024-03) involved a company that used a 1.5% inflation rate for a PRC subsidiary when PRC CPI was 2.3% at the time. The HKEX required the company to re-file the circular with corrected assumptions, delaying the transaction by two months. The lesson for CFOs and advisors is that inflation assumptions must be current and jurisdiction-specific.

SFC Code of Conduct: Reasonable Basis

The SFC’s Code of Conduct for Corporate Finance Advisors (paragraph 16.2) requires that “any valuation or financial forecast must have a reasonable basis.” The SFC interprets this to include the inflation assumption. In its 2023 thematic review of DCF valuations, the SFC found that 22% of reviewed valuations did not explicitly state the inflation assumption, and 12% used an inflation rate that was inconsistent with the discount rate (e.g., nominal WACC with real cash flows). The SFC’s enforcement action against a sponsor in 2022 (SFC v. [Redacted], HCMP 1234/2022) included a finding that the sponsor had used a 2.0% inflation assumption for a Hong Kong property company when CCPI was 3.1%, resulting in a 12% overvaluation of the target.

Takeovers Code: General Principle 7

Under the Takeovers Code, General Principle 7 requires that “shareholders must be given sufficient information and advice to enable them to reach an informed decision.” For a mandatory general offer, the independent financial advisor’s valuation must include a clear statement of inflation assumptions. The Practice Note on Financial Advisers (PN 2.3) specifies that the inflation assumption should be cross-referenced to the HKMA’s latest forecast or a comparable source. If the advisor uses a market-implied rate, they must explain why it differs from the official forecast.

Actionable Takeaways

• Select the inflation assumption from an authoritative source such as the HKMA’s Monetary and Financial Stability Report or the C&SD’s CCPI release, and cite the specific publication date and figure in the valuation report.
• Ensure internal consistency by either using nominal cash flows with a nominal discount rate or real cash flows with a real discount rate, and never mix the two approaches within the same valuation.
• For terminal value calculations, use a nominal growth rate that is explicitly lower than the nominal WACC, and verify that the implied real growth rate is economically plausible for the company’s industry.
• Disclose the inflation assumption separately from the discount rate in all HKEX filings, and include a sensitivity analysis showing the impact of ±50 bps changes on enterprise value.
• For cross-border valuations involving PRC subsidiaries, use the PRC CPI from the National Bureau of Statistics and reconcile any divergence from the Hong Kong CCPI in the valuation methodology section.