This online appendix provides some results omitted in the paper entitled Interest rate model with investor attitude and text mining by Nakatani et al. (2019).Let (Ω, F, {F} 0≤t≤T , P ) be a filtered probability space satisfying the usual conditions. We consider an economy with a representative agent and an endowment to the agent. Then, in equilibrium where the agent consumes all the given endowment at each instant, the agent's optimal consumption must be equal to the endowment process. Hence, let us assume a nonnegative consumption (i.e. endowment) process c exogenously whose expected return and volatility depend on a R l -valued state vector x, as the {F t }-adapted progressively measurable process satisfying the following stochastic differential equations (SDEs):Here, while the economy is driven by specific Brownian motions representing fundamental risk sources, the agent is not certain about all Brown motions. The agent thinks there is fundamental uncertainty about some of these fundamental risks, Brownian motions. We follow Nisimura, Sato and Takahashi (2019) formulating that under fundamental uncertainty about them, the representative agent does not face a single probability measure, but a set of probability measures. In particular, in the diffusion process framework, we postulate that the agent's fundamental uncertainty is represented by a set of different Brownian motions, i.e. a set of d-dimensional Brownian motions B λ1,λ2 characterized by the equation (4) with a particular set of stochastic processes, (5) below. Moreover, the representative agent may be "conservative" about the fundamental uncertainty for some Brownian motions (in the sense that the agent considers their worst possible case), * The views expressed in this paper are our own and do not reflect the institutions we are affiliated with. Financial supports from CARF at the University of Tokyo and JSPS KAKEN(S) #18H05217 are gratefully acknowledged. † Mitsubishi UFJ Trust Investment Technology Institute Co., Ltd. ‡ The views expressed here are those of the author and do not represent the official views of MTEC.