I think people wrongly infer this because he did something similar in his hedge fund Empirica. But there he had clients and couldn't take much mark to market risk. Especially because they were already bleeding daily from the 10% risk in options. I doubt Taleb puts 90% of his money in T-Bills and thinks it's all safe, especially given how much he criticized Bernanke for QEBy 'safe' Taleb means cash / T-bills, not all-weather / permanent-portfolio.