LaTeX Forum

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\begin{document}

\begin{equation}
 \begin{aligned}
0 &= \frac{\bar{E}_t\left[s_{t+1}\right]-s_t+i_t^{*}-i_t}{\theta\sigma_{s}^2}-h_t\\
\Leftrightarrow \underbrace{\bar{E}_t\left[s_{t+1}\right]-s_t &= i_t-i_t^{*}}_{\text{Ungedeckte Zinsparität}}\underbrace{+\theta\sigma_{s}^2 h_t}_{\text{Risikoprämie}}
 \end{aligned}
\end{equation} 

\end{document}

\begin{equation}
 \begin{aligned} 
0 &= \frac{\bar{E}_t\left[s_{t+1}\right]-s_t+i_t^{*}-i_t}{\theta\sigma_{s}^2}-h_t\\
\Leftrightarrow \underbrace{\bar{E}_t\left[s_{t+1}\right]-s_t &= i_t-i_t^{*}}_{\text{Ungedeckte Zinsparität}}\underbrace{+\theta\sigma_{s}^2 h_t}_{\text{Risikoprämie}}
 \end{aligned} 
\end{equation}