Geographic Concentration — Single-State Banks

Concentration risk — banks with most of their branches packed into a single state lack the geographic diversification regulators prefer, and concentrated portfolios are easier targets for localized fraud schemes (regional real-estate fraud, single-employer payroll fraud). Compute, for each bank, the share of its branches that sit in the bank's HQ state (institutions.state). Flag banks where 80%+ of branches are in the HQ state AND they have at least 5 branches. Show name, state, total_branches, hq_branches, hq_share_pct (rounded to 1 decimal). Order by hq_share_pct desc, then total_branches desc. Top 15.