2016. While some economists consider an increase in the stock market to have a "wealth effect" that increases economic growth, economists like Former Dallas Federal Reserve Bank President Richard Fisher believe those effects are limited. Causes of wealth inequality Essentially, the wealthy possess greater financial opportunities that allow their money to make more money. Earnings from the stock market or mutual funds are reinvested to produce a larger return. Over time, the sum that is invested becomes progressively more substantial. Those who are not wealthy, however, do not have the resources to enhance their opportunities and improve their economic position. Rather, "after debt payments, poor families are constrained to spend the remaining income on items that will not produce wealth and will depreciate over time." Scholar David B. Grusky notes that "62 percent of households headed by single parents are without savings or other financial assets." Net indebtedness generally prevents the poor from having any opportunity to accumulate wealth and thereby better their conditions. Economic inequality is also a result of difference in income. Factors that contribute to this gap in wages are things such as level of education, labor market demand and supply, gender differences, growth in technology, and personal abilities. The quality and level of education that a person has often corresponds to their skill level, which is justified by their income. Wages are also determined by the "market price of a skill" at that current time. Although gender inequality is a separate social issue, it plays a role in economic inequality. According to the U.S. Census Report, in America the median full-time salary for women is 77 percent of that for men. Also contributing to the wealth inequality in the U.S., both unskilled and skilled workers are being replaced by machinery. The Seven Pillars Institute for Global Finance and Ethics argues that because of this "technological advance", the income gap between workers and owners has widened. Income inequality contributes to wealth inequality. For example, economist Emmanuel Saez wrote in June 2016 that the top 1% of families captured 52% of the total real income (GDP) growth per family from 2009 to 2015. From 2009 to 2012, the top 1% captured 91% of the income gains. Nepotism perpetuates and increases wealth inequality. Wealthy families pass down their assets allowing future generations to develop even more wealth. The poor, on the other hand, are less able to leave inheritances