You might have invested in your retirement via 401(k) accounts, one of the primary vehicles by which we shoot for financial security after we stop working. We trust our employers to provide these plans at a low cost.

Mark Mensack, a new cop on the 401(k) retirement beat, says we and our corporate plan sponsors might be getting ripped off. And he wants to help: Mensack's expertise is in the area of 401(k) hidden fees and ethical issues in the retirement-plan marketplace. He has 14 years of experience as a financial adviser with broker-dealers, and three as a registered investment adviser.

Why does Mensack care so much about this? A former Army officer with a master's degree from the University of Pennsylvania, he has more than a passing interest in ethics and fee conflicts. His final active-duty assignment was on the faculty of the U.S. Military Academy at West Point, N.Y. Then working as a financial adviser at Morgan Stanley, the Cherry Hill resident contended he found wrongdoing involving what he called a "pay-to-play scheme" in $4 billion of 401(k) assets that Morgan Stanley administered.

Mensack reported his ethical and legal concerns through management ranks and, eventually, all the way to Morgan Stanley's board of directors, and was promptly let go.

Mensack works as an independent reviewer of 401(k) plans and their hidden fees, and he blogs about the issues ( For instance, he says a 2011 AARP study found that 71 percent of the 72 million Americans currently invested in a 401(k) plan don't realize they are paying 401(k) fees. "This is largely due to the fact that so many 401(k) products bury fees deep within fine print or obscure them in complex formulas or percentages," he said.

The U.S. Department of Labor is catching on to the game, and found that a 1 percent difference in fees over the average American's 35-year working career could reduce that person's retirement nest egg by as much as 28 percent.

One of the best examples in what Mensack calls this 401(k) "witch's brew" is Vanguard funds within certain group annuity 401(k) products. Vanguard has a respected reputation for low-cost, quality mutual funds, and generally, expenses aren't an issue with Vanguard funds or Vanguard 401(k) products, he explained.

Standard & Poor's 500 index funds, like those offered by Fidelity or Vanguard or other low-cost mutual fund firms, generally offer fabulously cheap expense ratios of around 0.18 percent. However, in one 401(k) plan Mensack reviewed, the expense ratio of the S&P 500 fund was 0.53 percent - almost 300 percent higher. Worse, employees were paying an additional 0.50 percent wrap fee, pushing the total cost nearly 600 percent over retail. Unfortunately, the plan sponsor mistakenly thought he or she had chosen a low-cost 401(k) product.

You can read more about Mensack's contempt for the proposed regulator of registered investment advisers (FINRA) and his fight with Morgan Stanley here ( or at his website.