Margin requirements are designed to control the default risk inherent to commitments undertaken by traders writing options. Much like similar institutions, the Tel Aviv Stock Exchange first adopted a system based on the Standard Portfolio Analysis of Risk (SPAN), which sets required levels of...

An explanation is provided for the following seemingly unrelated pieces of evidence concerning unions and pension plans in the United States: 1) The pension wealth of union members is greater than that of other workers, but 2) union pension plans are more often underfunded and 3) more likely to...

Recent empirical findings by Allan and Clark (NBER WP1677, 1985) show that the pension wealth of union beneficiaries is dramatically greater than that of nonunion beneficiaries. Other findings by these and other authors show that union pension plans are more likely to be underfunded. Ippolito...