Most workers do not contribute the maximum allowable amount to employer-sponsored tax-deferred retirement plans. The share of maximum contributors increased between 1990 and 2003, as did the percentage of participants who contribute the maximum or at least 10 percent of earnings. But virtually all the growth in maximum contributors came from groups with high shares of maximum contributors in 1990. Recent increases in contribution limits can be expected to reduce shares of maximum contributors, but raise relative shares of maximum contributors among high-earning and education groups. Increases in contribution limits do little to increase retirement preparedness among lower-income groups.