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Rate from Lump Sum

Find the continuous compounding rate.

When to use: Use for continuous-time finance calculations.

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Formula

k=ln(FV/PV)nk = \frac{\ln(FV/PV)}{n}

Variables

SymbolNameDescriptionUnit
kContinuous RateContinuously compounded rate%
FVFuture ValueEnding value$
PVPresent ValueStarting value$
nNumber of YearsTime periodyears

Real-Life Examples

Example 1: Continuous Return

An investment went from $10,000 to $25,000 in 15 years. Continuous rate?

Given

FV = 25,000PV = 10,000n = 15

Step-by-Step

1.k = ln(25000/10000) / 15
2.k = ln(2.5) / 15
3.k = 0.9163 / 15
4.k = 0.0611 = 6.11%
Result:0.06

The continuously compounded return was about 6.11%.

Example 2: Bond Yield

A zero-coupon bond priced at $600 matures at $1,000 in 10 years. Continuous yield?

Given

FV = 1,000PV = 600n = 10

Step-by-Step

1.k = ln(1000/600) / 10
2.k = ln(1.6667) / 10
3.k = 0.5108 / 10
4.k = 0.0511 = 5.11%
Result:0.05

The continuous yield is about 5.11%.

Frequently Asked Questions

A continuously compounded return assumes growth happens at every instant rather than at discrete intervals. It equals ln(FV/PV)/n, using the natural logarithm. It is commonly used in quantitative finance and options pricing.

Continuous returns are mathematically convenient because they are additive across time periods (unlike discrete returns, which must be compounded). A 5% continuous return for 2 years is simply 10%, making multi-period analysis simpler.

To convert a continuous rate to an effective annual rate: EAR = e^k - 1. To go the other way: k_continuous = ln(1 + EAR). For example, a 6% continuous rate equals an effective rate of e^0.06 - 1 = 6.18%.