capn: Captial Asset Pricing for Nature

• This repository develops and distributes a testing version of the R package capn.

• The latest stable release is available on CRAN.

• Data and code in this repository are subject to change.

GitHub Repository maintained by: Seong D. Yun
Department of Agricultural Economics
Mississippi State University
yunsd2004@gmail.com
https://sites.google.com/site/yunsd2004/
Last updated: Feb 16, 2026

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1 capn R-package

The capn package implements approximation methods for natural capital asset prices proposed in:

• Abbott, Fenichel, and Yun (2026)
• Fenichel and Abbott (2014)
• Fenichel, Abbott, and Yun (2018)
• Hashida and Fenichel (2022)
• Yun et al. (2017)
• Subsequent methodological extensions

2 Getting started:

2.1. Install the Latest Stable Version from CRAN:

The official release of capn is available on CRAN:

    ## In R
    install.packages("capn")
    library(capn)

2.2. Install the Development (Testing) Version from GitHub:

A development version is available for testing purposes.

    ## Need to install devtools packages
    install.packages("devtools")
    ## Then use
    devtools::install_github("ysd2004/capn")
    library(capn)

3 Authors

Seong D. Yun, Associate Professor, Mississippi State University (yunsd2004@gmail.com)

Eli P. Fenichel, Professor, Yale University (eli.fenichel@yale.edu)

Joshua K. Abbott, Professor, Arizona State Unviersity (joshua.k.abbott@asu.edu)

Maintainer and Bug Reports: Seong Yun (yunsd2004@gmail.com)

4 Citation

Please cite the software in academic publications.

4.1. capn (stable and latest) from CRAN

use citation();

citation(package = "capn")
 
# To cite package 'capn' in publications use:

To cite package ‘capn’ in publications use:

  Seong D. Yun, Eli P. Fenichel and Joshua K. Abbott (2017). capn: Capital Asset Pricing for
  Nature. R package version 1.0.0. https://CRAN.R-project.org/package=capn

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {capn: Capital Asset Pricing for Nature},
    author = {Seong Do Yun and Eli P. Fenichel and Joshua K. Abbott},
    year = {2017},
    note = {R package version 1.0.0},
    url = {https://CRAN.R-project.org/package=capn},
  }

4.2. capn (testing and development) version (GitHub)

Seong D. Yun, Eli P. Fenichel and Joshua K. Abbott (year). capn: Capital Asset Pricing for Nature. R package version (version /#). https://github.com/ysd2004/capn

5 References

The methods and examples in capn are available from:

• Abbott, J. K., E. P. Fenichel, and S. D. Yun, 2026, "Risky (Natural) Assets: Stochasticity, Nonconvexity, and the Value of Natural Capital"

• Fenichel, E. P. and J. K. Abbott, 2014, "Natural Capital: From Metaphor to Measurement," Journal of the Association of Environmental and Resource Economists, 1:1-27. (https://doi.org/10.1086/676034)

• Fenichel, E. P., J. K. Abbott, and S. D. Yun, 2018, "The Nature of Natural Capital and Ecosystem Income", Handbook of Environemntal Economics (P. Daguta, S. K. Pattanayak, and V. K. Smith eds), 4: 85-142, Elsevier (https://doi.org/10.1016/bs.hesenv.2018.02.002)

• Hashida, Y. and E. P. Fenichel, 2022, "Valuing Natural Capital When Management Is Dominated by Periods of Inaction", American Journal of Agricultural Economics, 104(2): 791-811. (https://doi.org/10.1111/ajae.12250)

• Yun, S. D., B. Huniczak, J. K. Abbott, and E. P. Fenichel, 2017, "Ecosystem-based Management and the Wealth of Ecosystems," Proceedings of the National Academy of Sciences, 114(25): 6539-6544. (https://doi.org/10.1073/pnas.1617666114)

6 Development History

Below is a chronological record of the development of the capn R package.

• 2-16-2026: Released v2.0.0 on GitHub.

• 1-17-2026: Initiated public testing for v2.0.0.

• 12-13-2020: Activated the GitHub repository for capn.

• 02-08-2020: Development of v2.0.0 initiated.

• 11-25-2019: Completed multiple-stock v-approximation algorithms.

• 04-28-2019: Implemented multi-stock v-approximation for the stochastic capn model.
       vaprox() became available for multiple-stock cases.

• 11-05-2018: Corrected code errors in the stochastic multi-stock v-approximation.

• 05-21-2018: Implemented single-stock v-approximation for the stochastic capn model.
       - chebbasisgen() added for higher-order derivatives.
       - vaprox() available for the single-stock case.

• 03-20-2018: Initiated development of the stochastic {capn} model.

• 06-15-2017: Official release of v1.0.0 on CRAN.

• 03-30-2016: Released beta version v0.0.3 via Seong Yun and Eli Fenichel's website.

• 03-20-2016: Promoted beta version v0.0.2 at the 2016 Natural Capital Symposium (Stanford University).

• 03-16-2016: Released beta version v0.0.2 via Seong Yun and Eli Fenichel's website.

• 01-27-2016: Package renamed to {capn} (previously {nsim}).

• 01-18-2016: Released beta version v0.0.1 to the development group under the name {nsim}.

• 08-17-2015: Team meeting at Yale University.

• 08-03-2015: Development team formed to create the R package.