FRANKFURT (Reuters) – Germany’s financial regulator BaFin considers another sudden and sharp interest rate hike to be one of the greatest threats currently facing the banking sector, according to a report published on Monday. The abrupt rise in interest rates is already putting pressure on the profitability of many banks by causing losses in the securities portfolios of some institutes, the regulator said in the report. “Another sudden and sharp rise in interest rates would put some institutions under severe strain,” it added. “For many smaller banks, hidden reserves as a first line of defence…