By using the Hao-Clem model, we analyzed the equilibrium magnetization of the grain-aligned HgBa2Ca4Cu5O12+y (Hg1245) with T-c similar or equal to 108 K. We obtained thermodynamic parameters, such as the penetration depth [lambda(ab)(0)] and the coherence length [xi(ab)(0)] from the thermodynamic critical field [H-c] and the Ginzburg-Landau parameter [kappa]. Compared to the four layered superconductor HgBa2Ca3Cu4O10+y (Hg1234), the obtained penetration depth was slightly increased indicating that the Cooper pair density of Hg1245 was decreased, which was one of the reasons why the transition temperature (T-c) of the Hg1245 did not increase as compared to the Hg1234. The expected increase of T-c for the material with the more CuO2 planes was not achieved because of the insufficient doping of the Cooper pairs while adding CuO2 planes. (C) 2009 Elsevier B.V. All rights reserved.