I am struggling with multicolumn. What I want is equal spacing between the three columns. Without multicolumn, there is not enough space because of the Panel rows. With multicolumn, it just Looks bad. Does anyone know how I could handle this? I guess the first column just has to move a bit to the right that the table Looks at least decent...
\documentclass[a4paper, 12pt]{article}
\DeclareUnicodeCharacter{FB01}{fi}
\DeclareUnicodeCharacter{FB02}{fl}
%\usepackage[space]{grffile}
\usepackage{apacite}
\usepackage{makecell}
\usepackage{afterpage}
\usepackage{dblfloatfix}
\usepackage[referable]{threeparttablex}
\usepackage[paper=portrait,pagesize]{typearea}
\usepackage{mleftright}
\usepackage{lscape}
\usepackage{a4wide}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[onehalfspacing]{setspace}
\usepackage{float, afterpage, rotating, graphicx}
\usepackage[dvipsnames]{xcolor}
\usepackage{tikz, epstopdf,pgfplots}
\usepackage{longtable, booktabs, tabularx}
\usepackage{fancyvrb, moreverb, relsize}
\usepackage{eurosym, calc, chngcntr}
\usepackage{amsmath, amssymb, amsfonts, amsthm, bm}
\usepackage{mathtools}
\DeclareMathOperator*{\argmin}{arg\,min}
\DeclareMathOperator*{\argmax}{arg\,max}
\usepackage[labelfont={bf}, skip=5pt]{caption}
\usepackage{mdwlist}
\usepackage{tabularx, booktabs}
\newcolumntype{C}{>{\centering\arraybackslash}X}
\usepackage{xfrac}
\usepackage{setspace,geometry}
\usepackage{xcolor}
\usepackage{lmodern}
\usepackage{upgreek}
\usepackage{afterpage}
\usepackage{wrapfig}
\usepackage{pdflscape}
\usepackage{multirow, booktabs, makecell, caption}
\usepackage{fancyhdr}
\usepackage[toc]{glossaries}
\usepackage{subcaption}
\usepackage{lipsum}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{eurosym}
\usepackage{amsfonts}
\usepackage{booktabs}
\usepackage{abstract}
\usepackage{dcolumn}
\usepackage{graphicx}
\usepackage[hyphens]{url}
\usepackage{acronym}
\usepackage[english]{babel}
\usepackage[round, sort&compress]{natbib} %sort&compress orders in text citation automatically
\usepackage{pgfplots}
\usepackage{threeparttable}
\usepackage{siunitx} %setze S in Tabelle, um nach dem Punkt auszurichten
\usepackage[export]{adjustbox}
\usepackage{etoolbox}
\usepackage[hyperfootnotes=false]{hyperref}
\usepackage{footnotebackref}
\usepackage{appendix}
\usepackage[bottom,hang,flushmargin]{footmisc} %footnotes always appear on bottom and not end of text on single page
\geometry{a4paper, top=30mm, left=30mm, right=30mm, bottom=30mm,headsep=10mm, footskip=12mm}
%try to prevent widows and orphans (single lines on top/bottom of page)
\widowpenalty10000
\clubpenalty10000
\begin{document}
\begin{table}[t!]
\centering
\caption{Summary of strategy performances}
\label{tab2:summary}
\begin{threeparttable}
\begin{tabular*}{\linewidth}{l@{\extracolsep{\fill}}*{3}{c}}
\toprule
& \makecell{\textbf{Individual} \\ \textbf{Cryptocurrencies}} & \makecell{\textbf{Equally-weighted} \\ \textbf{benchmark}} & \makecell{\textbf{Risk-based} \\ \textbf{Strategies}} \\
\midrule
\multicolumn{2}{l}{\textit{Panel A: Risk and Return}} & & \\
Mean & \textbf{--} & \textbf{+} & \textbf{--} \\
SD & \textbf{--} & \textbf{--} & \textbf{+} \\
SR & \textbf{--} & \textbf{--} & \textbf{+} \\
Min & \textbf{--} & \textbf{--} & \textbf{+} \\
Max & \textbf{--} & \textbf{--} & \textbf{+} \\
Skew & \textbf{--} & \textbf{--} & \textbf{+} \\
Kurt & \textbf{--} & \textbf{--} & \textbf{+} \\
\midrule
\multicolumn{2}{l}{\textit{Panel B: Tail and Extreme Risk}} & & \\
VaR (5\%) & \textbf{--} & \textbf{--} & \textbf{+} \\
VaR (1\%) & \textbf{--} & \textbf{--} & \textbf{+} \\
CVaR(5\%) & \textbf{--} & \textbf{--} & \textbf{+} \\
CVaR (1\%)& \textbf{--} & \textbf{--} & \textbf{+} \\
DD & \textbf{--} & \textbf{--} & \textbf{+} \\
MD & \textbf{--} & \textbf{--} & \textbf{+} \\
LPM & \textbf{--} & \textbf{--} & \textbf{+} \\
\midrule
\multicolumn{2}{l}{\textit{Panel C: Conditional Performance}} & & \\
Bull market & \textbf{--} & \textbf{--} & \textbf{+} \\
Bear market & \textbf{--} & \textbf{--} & \textbf{+} \\
\bottomrule
\end{tabular*}
\begin{tablenotes}[para,flushleft]
\footnotesize
\item\hspace{-2.5pt}\noindent\textit{Note:} The table
provides xx
\end{tablenotes}
\end{threeparttable}
\end{table}
\end{document}
apacitepackage and thenatbib. Load one or the other, but not both. And don't load thea4widepackage if you load thegeometrypackage. – Mico Sep 26 at 19:34