From 0811b116b992ac977630c7deb687f995d89dc9a6 Mon Sep 17 00:00:00 2001
From: Tyler Hoang <tyler@tylerhoang.xyz>
Date: Mon, 18 May 2026 01:27:30 -0700
Subject: feat: add _run_dcf, _run_ev_ebitda, _run_ev_revenue,
 _run_price_to_book

---
 backend/app/services/data_service.py | 134 +++++++++++++++++++++++++++++++++++
 1 file changed, 134 insertions(+)

(limited to 'backend/app/services/data_service.py')

diff --git a/backend/app/services/data_service.py b/backend/app/services/data_service.py
index 9a88005..c7077db 100644
--- a/backend/app/services/data_service.py
+++ b/backend/app/services/data_service.py
@@ -322,6 +322,140 @@ def _build_multiple_result(raw: dict) -> dict:
     }
 
 
+def _run_dcf(
+    fcf_series: "pd.Series",
+    shares_outstanding: float,
+    wacc: float = 0.10,
+    terminal_growth: float = 0.03,
+    projection_years: int = 5,
+    total_debt: float = 0.0,
+    cash_and_equivalents: float = 0.0,
+    preferred_equity: float = 0.0,
+    minority_interest: float = 0.0,
+) -> dict:
+    if fcf_series.empty or shares_outstanding <= 0:
+        return {}
+    historical = fcf_series.sort_index().dropna().astype(float).values
+    if len(historical) < 2:
+        return {}
+    if wacc <= 0:
+        return {"error": "WACC must be greater than 0%."}
+    if terminal_growth >= wacc:
+        return {"error": "Terminal growth must be lower than WACC."}
+
+    growth_rate = _dcf_capped_growth_rate(fcf_series)
+    if growth_rate is None:
+        growth_rate = 0.05
+
+    base_fcf = float(historical[-1])
+    if base_fcf <= 0:
+        return {
+            "error": (
+                "DCF is not meaningful with zero or negative base free cash flow. "
+                "Use comps, EV/EBITDA, or adjust the model after underwriting a credible FCF turnaround."
+            )
+        }
+
+    projected = [base_fcf * ((1 + growth_rate) ** yr) for yr in range(1, projection_years + 1)]
+    discounted = [fcf / ((1 + wacc) ** i) for i, fcf in enumerate(projected, start=1)]
+    fcf_pv_sum = float(sum(discounted))
+
+    terminal_fcf = float(projected[-1]) * (1 + terminal_growth)
+    terminal_value = terminal_fcf / (wacc - terminal_growth)
+    terminal_value_pv = terminal_value / ((1 + wacc) ** projection_years)
+
+    enterprise_value = fcf_pv_sum + terminal_value_pv
+    total_debt = float(total_debt or 0.0)
+    cash_and_equivalents = float(cash_and_equivalents or 0.0)
+    preferred_equity = float(preferred_equity or 0.0)
+    minority_interest = float(minority_interest or 0.0)
+
+    net_debt = total_debt - cash_and_equivalents
+    equity_value = enterprise_value - net_debt - preferred_equity - minority_interest
+    intrinsic_value_per_share = equity_value / shares_outstanding
+
+    return {
+        "intrinsic_value_per_share": intrinsic_value_per_share,
+        "enterprise_value": enterprise_value,
+        "equity_value": equity_value,
+        "net_debt": net_debt,
+        "cash_and_equivalents": cash_and_equivalents,
+        "total_debt": total_debt,
+        "terminal_value_pv": terminal_value_pv,
+        "fcf_pv_sum": fcf_pv_sum,
+        "growth_rate_used": growth_rate,
+        "base_fcf": base_fcf,
+    }
+
+
+def _run_ev_ebitda(
+    ebitda: float,
+    total_debt: float,
+    total_cash: float,
+    preferred_equity: float,
+    minority_interest: float,
+    shares_outstanding: float,
+    target_multiple: float,
+) -> dict:
+    if not ebitda or ebitda <= 0:
+        return {}
+    if not shares_outstanding or shares_outstanding <= 0:
+        return {}
+    if not target_multiple or target_multiple <= 0:
+        return {}
+    implied_ev = ebitda * target_multiple
+    net_debt = (total_debt or 0.0) - (total_cash or 0.0)
+    other_claims = (preferred_equity or 0.0) + (minority_interest or 0.0)
+    equity_value = implied_ev - net_debt - other_claims
+    return {
+        "implied_ev": implied_ev,
+        "net_debt": net_debt,
+        "equity_value": equity_value,
+        "implied_price_per_share": equity_value / shares_outstanding,
+        "target_multiple_used": target_multiple,
+    }
+
+
+def _run_ev_revenue(
+    revenue: float,
+    total_debt: float,
+    total_cash: float,
+    preferred_equity: float,
+    minority_interest: float,
+    shares_outstanding: float,
+    target_multiple: float,
+) -> dict:
+    if not revenue or revenue <= 0:
+        return {}
+    if not shares_outstanding or shares_outstanding <= 0:
+        return {}
+    if not target_multiple or target_multiple <= 0:
+        return {}
+    implied_ev = revenue * target_multiple
+    net_debt = (total_debt or 0.0) - (total_cash or 0.0)
+    other_claims = (preferred_equity or 0.0) + (minority_interest or 0.0)
+    equity_value = implied_ev - net_debt - other_claims
+    return {
+        "implied_ev": implied_ev,
+        "net_debt": net_debt,
+        "equity_value": equity_value,
+        "implied_price_per_share": equity_value / shares_outstanding,
+        "target_multiple_used": target_multiple,
+    }
+
+
+def _run_price_to_book(book_value_per_share: float, target_multiple: float) -> dict:
+    if not book_value_per_share or book_value_per_share <= 0:
+        return {}
+    if not target_multiple or target_multiple <= 0:
+        return {}
+    return {
+        "implied_price_per_share": float(book_value_per_share) * float(target_multiple),
+        "target_multiple_used": float(target_multiple),
+        "book_value_per_share": float(book_value_per_share),
+    }
+
+
 @cached(FINANCIALS_CACHE)
 def get_financials(symbol: str, period: str = "annual") -> dict:
     sym = normalize_symbol(symbol)
-- 
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