Hybrid Securities, Corporate Finance & Equity-Linked Debt
Convertible Bond Parity, Premium & Breakeven Formula
Calculate Corporate Convertible Bond Conversion Ratio (Par / Conv_Price), Equity Conversion Parity Value, Dollar & Percentage Conversion Premium, and Coupon-vs-Dividend Income Payback Years.
Measure convertible bond asymmetric upside via Equity Parity and Coupon Carry Payback!
Public corporate Convertible Bonds combine fixed-income downside protection with an embedded call warrant to convert Par_Value ($1,000) into Conversion_Ratio = Par_Value / Conversion_Price common shares! Multiplying Conversion_Ratio by Current_Stock_Price gives Equity Conversion Value (Parity). Because investors value the bond floor protection, convertibles trade above parity by Conversion_Premium_$ = Bond_Market_Price - Parity (or Conversion_Premium_% = (Bond_Market_Price - Parity) / Parity). Institutional convertible desks evaluate how fast the convertible’s higher cash coupon recoups that dollar premium over owning the underlying common shares directly: Income_Breakeven_Years = Conversion_Premium_$ / (Annual_Bond_Coupon - Conversion_Ratio * Stock_Annual_Dividend)!
Verify on a Senior Convertible Note—Par_Value = $1,000 (B2), Stated_Conversion_Price = $50.00/sh (B3 -> Conversion Ratio = 20.0 shares/bond), Current_Stock_Price = $45.00/sh (B4 -> Equity Parity = 20 * $45 = $900.00 in E2), Convertible_Market_Price = $1,080.00 (B5), Bond_Coupon_Rate = 0.04 (4.0% = $40.00/yr, B6), and Common_Dividend_Per_Share = $0.50/yr (B7 -> 20 * $0.50 = $10.00/yr parity dividend): Dollar Conversion Premium is $1,080 - $900 = $180.00 (E3); Percentage Conversion Premium is 180 / 900 = 0.2000 (20.00% in E4); and Income Breakeven Payback is $180 / ($40 - $10) = 6.00 years (E5)!
| Convertible Bond Metric ($1,000 Par, $50 Conv, Stock=$45, Bond=$1,080, 4% Cpn, $0.50 Div) | Formula | Verified Output |
|---|---|---|
| Equity Conversion Value (Parity) | (Par / Conv_Price) * Stock_Price | $900.00 ($1,080 @ Stock=$54) |
| Dollar Conversion Premium ($) | Bond_Price - Equity_Parity | $180.00 ($0.00 @ Stock=$54) |
| Percentage Conversion Premium | (Bond_Price - Parity) / Parity | 0.2000 (20.00%; 0.0000 @ $54) |
| Income Payback Breakeven (Yrs) | Premium_$ / (Bond_Cpn - Ratio*Div) | 6.00 yrs (0.00 yrs @ Parity) |
Convertible Bond Coupon-Advantage Breakeven Years Formula
Validate positive Par, Conv_Price, Stock_Price, Bond_Price >= Parity, non-negative coupon/dividend, and flag "Negative Carry: Stock Div >= Coupon" when converted common dividends equal or exceed the bond coupon!
=LET(pr_v, B2, cv_p, B3, st_p, B4, bd_p, B5, cp_r, B6, dv_s, B7, IF(OR(pr_v <= 0, cv_p <= 0, st_p <= 0, bd_p <= 0, cp_r < 0, dv_s < 0), "Invalid Convertible Quote", LET(cv_r, pr_v / cv_p, pr_y, cv_r * st_p, IF(bd_p < pr_y, "Arbitrage: Bond Below Parity", LET(in_d, pr_v * cp_r - cv_r * dv_s, IF(in_d <= 0, "Negative Carry: Stock Div >= Coupon", ROUND((bd_p - pr_y) / in_d, 2)))))))Deep In-the-Money Parity Check ($54 Stock) & High-Dividend Negative Carry Check
Rally Stock_Price B4 to $54.00: Parity hits $1,080.00, Premium drops to 0%, and Breakeven hits 0.00 years! Or reset B4 = $45 and raise Common_Dividend B7 to $2.50/sh ($50/yr > $40 coupon): E5 flags "Negative Carry: Stock Div >= Coupon"!
=IF(OR(B2 <= 0, B3 <= 0, B4 <= 0, B5 <= 0, B6 < 0, B7 < 0), "Invalid Convertible Quote", ROUND((B5 - E2) / E2, 4))Try the example
Use the original values or change them to test your understanding.