Although they may have the money, affluent Americans are still dragging in devising a long-term college savings plan for their offspring, according to a newly released study.

Legg Mason Inc.'s 2012 Intergenerational Survey of College Finances investigated the differences in planning and expectations among three groups of parents with investable assets of $250,000 or more: those with children who have already graduated, those with children currently enrolled and those who are planning to send their children to college.

The report showed the growing popularity of 529 college savings plans among those parents who are still in the planning stages compared with those whose children have already graduated. But research indicated that a vast majority of parents used or plan to use their current income, or withdraw from other savings and nonqualified investment accounts, to pay for college expenses.

"Unfortunately, many parents, regardless of wealth and income, fund college expenses via current income or investment and savings accounts not specifically targeted to college saving," said John Kenney, head of Legg Mason Global Asset Allocation (LMGAA). "By beginning the college savings process earlier, parents take advantage of the tax savings afforded by 529 savings plans, and potentially free up other income and savings to fund their own retirement goals."

These affluent parents are striving to pay as much of their children's college expenses as possible, but the prevalent use of current income shows they are leaving money on the table by not using tax-advantaged savings programs, such as 529s, to the extent they could.

Kenney said even affluent families underfund their children's college savings, despite having resources to make additional savings. While 71% of those parents with children in college and 61% of those still in the planning stage say they can afford to save $500 per month or more for college expenses, those resources are either not being put to use early or efficiently enough.

Over one-third of those parents who realize they should have been saving more admitted they either did not know how much they needed to save or did not expect expenses to be so high, according to the survey. The numbers indicate there is an opportunity to provide parents with more education and guidance about putting a coordinated plan together.

Although 48% of those parents surveyed noted that they had paid for all or most of their own college education, they were committed to ensuring their children did not. Among those parents whose children already graduated, 82% paid all or most of their children's college expenses versus 83% for those with children currently enrolled and 84% for those who still plan to send their children to college.

The survey was conducted online by Mathew Greenwald & Associates and commissioned by Legg Mason from March 26 to 31. Over 1,000 respondents with over $250,000 in investable assets were equally split between men and women of whom 405 had children not yet in college, 248 have children in college and 358 had children who were out of college and under the age of 40.

Legg Mason is a global asset management firm with $643 billion in assets under management as of March 31, 2012.