Mark's dad and sister both work for Procter & Gamble. He has lived in Cincinnati, OH $($the headquarters for P&G$)$ his entire life. After graduating from college, Mark landed a job a P&G in the diaper division in a brand management capacity. He decides to allocate his $401($k$)50\%$ to the Vanguard Total Stock Market Index, $20\%$ to the Vanguard International Growth Fund, and $30\%$ into P&G stock. Which bias most likely explains this allocation mix?