The bottom line of the table grosses up the numbers for industry totals, by assuming that 80% is covered by the top 10 firms. For the margin lending we assume 75% is covered by member of the NYSE. The main point to note is that counterparty exposure differs considerably between the prime brokers, with higher risk-taking firms (to generate higher returns) showing high exposures relative to tier 1 capital, and more conservative firms showing much lower ratios. The total exposure of the top 10 firms is about USD trillion, and total Tier 1 capital is around.
