Any investment strategy that places your net worth in a handful of companies, in one sector, in one country, is risky by definition.
Reducing the risk of your portfolio is not about trying to guess or "foresee" which company will go bust in order to avoid that stock, but by diversifying to the extent that you need not be worried about individual companies.
Ignorance of these basic facts, or belief in the "consensus" view of a very incestuous Irish finance community (see irish pension funds) is no excuse.