In this paper an iterative method is proposed to solve a partial differential equation (PDE) with free boundary arising from pricing corporate bond with credit grade migration risk. A iterative algorithm is designed to construct two sequences of fixed internal boundary problems, which produce two weak solution sequences. It is proved that both weak solution sequences are convergent. In each iteration step, an implicit-upwind difference scheme is used to solve the fixed internal boundary problem. It is shown that the scheme is stable and first-order convergent. Numerical experiments verify that the limit of the weak solution sequence is the solution of the free boundary problem. This method simplifies the free boundary problem solving, ensures the stability of the discrete scheme and reduces the amount of calculation.
Citation: Zhongdi Cen, Jian Huang, Aimin Xu, Anbo Le. An iterative method for solving a PDE with free boundary arising from pricing corporate bond with credit rating migration[J]. AIMS Mathematics, 2023, 8(2): 3286-3302. doi: 10.3934/math.2023169
In this paper an iterative method is proposed to solve a partial differential equation (PDE) with free boundary arising from pricing corporate bond with credit grade migration risk. A iterative algorithm is designed to construct two sequences of fixed internal boundary problems, which produce two weak solution sequences. It is proved that both weak solution sequences are convergent. In each iteration step, an implicit-upwind difference scheme is used to solve the fixed internal boundary problem. It is shown that the scheme is stable and first-order convergent. Numerical experiments verify that the limit of the weak solution sequence is the solution of the free boundary problem. This method simplifies the free boundary problem solving, ensures the stability of the discrete scheme and reduces the amount of calculation.
[1] | R. A. Adams, J. J. Fournier, Sobolev spaces, $2^{nd}$ edition, New York: Academic Press, 2003. |
[2] | X. Chen, J. Liang, A free boundary problem for corporate bond pricing and credit rating under different upgrade and downgrade thresholds, SIAM J. Financ. Math., 12 (2021), 941–966. http://dx.doi.org/10.1137/20M1343592 doi: 10.1137/20M1343592 |
[3] | C. Clavero, J. L. Gracia, G. I. Shishkin, L.P. Shishkina, Grid approximation of a singularly perturbed parabolic equation with degenerating convective term and discontinuous right-hand side, Int. J. Numer. Analy. Model., 10 (2013), 795–814. http://www.math.ualberta.ca/ijnam/Volume10-1.htm |
[4] | L. C. Evans, Partial differential equations, $2^{nd}$ edition, New York: American mathematical society, 2010. |
[5] | P. A. Farrell, A. F. Hegarty, J. J. H. Miller, E. O'Riordan, G. I. Shishkin, Global maximum norm parameter-uniform numerical method for a singularly perturbed convection-diffusion problem with discontinuous convection coefficient, Math. Comput. Model., 40 (2004), 1375–1392. https://doi.org/10.1016/j.mcm.2005.01.025 doi: 10.1016/j.mcm.2005.01.025 |
[6] | B. Hu, J. Liang, Y. Wu, A free boundary problem for corporate bond with credit rating migration, J. Math. Analy. Appl., 428 (2015), 896–909. https://doi.org/10.1016/j.jmaa.2015.03.040 doi: 10.1016/j.jmaa.2015.03.040 |
[7] | J. Kandilarov, L. Vulkov, Front fixing finite difference method for pricing a corporate bond with credit rating migration, In: International conference on numerical methods and applications, 11189 (2019), 416–423. http://dx.doi.org/10.1007/978-3-030-10692-8_47 |
[8] | H. Leland, Corporate debt value, bond covenants, and optimal capital structure, J. Financ., 49 (1994), 1213–1252. https://doi.org/10.2307/2329184 doi: 10.2307/2329184 |
[9] | L. Jiang, Mathematical modeling and methods of option pricing, Singapore: World Scientific Publishing, 2005. |
[10] | J. Liang, J. Bao, C. Zeng, Pricing on a defautable and callable corporate bond with credit rating migration under the structure framework, in Chinese, J. Syst. Eng., 33 (2018), 793–822. https://doi.org/10.13383/j.cnki.jse.2018.06.008 doi: 10.13383/j.cnki.jse.2018.06.008 |
[11] | J. Liang, X. Chen, Y. Wu, H. M. Yin, On a corporate bond pricing model with credit rating migration risks and stochastic interest rate, Quant. Financ. Econ., 1 (2017), 300–319. https://doi.org/10.3934/QFE.2017.3.300 doi: 10.3934/QFE.2017.3.300 |
[12] | J. Liang, C. Zeng, Corporate bonds pricing under credit rating migration and structure framework, in Chinese, Appl. Math. A J. Chin. Uni., 30 (2015), 61–70. https://doi.org/10.13299/j.cnki.amjcu.001850 doi: 10.13299/j.cnki.amjcu.001850 |
[13] | J. Liang, Y. J. Zhao, Utility indifference valuation of corporate bond with credit rating migration by structure approach, Econ. Model., 54 (2016), 339–346. https://doi.org/10.1016/j.econmod.2015.12.002 doi: 10.1016/j.econmod.2015.12.002 |
[14] | E. O'Riordan, G. I. Shishkin, Singularly perturbed parabolic problems with non-smooth data, J. Comput. Appl. Math., 166 (2004), 233–245. https://doi.org/10.1016/j.cam.2003.09.025 doi: 10.1016/j.cam.2003.09.025 |
[15] | Y. Wu, J. Liang, B. Hu, A free boundary problem for defaultable corporate bond with credit rating migration risk and its asymptotic behavior, Discrete Cont. Dyn.-B, 25 (2020), 1043–1058. https://doi.org/10.3934/dcdsb.2019207 doi: 10.3934/dcdsb.2019207 |