NEW YORK (CNN/Money) - Securities regulators and lawmakers are looking into sales of investments, such as mutual funds and life insurance, to military personnel that they suspect might be unsuitable for those buying them, according to a published report.

The New York Times reported Thursday that some members of Congress say they are concerned the young recruits on U.S. military bases are being treated as a captive market by the firms now under investigation. The costs of the investments under scrutiny might not be adequately explained to the recruits, the newspaper said.

The paper, citing sources close to the matter, say the probe focuses on the sales practices of Fort Worth, Texas-based First Command Financial Planning, which sells mutual funds, insurance and banking services to officers of U.S. military bases around the world

The investigation is looking into First Command's heavily promoted "contractual plans," which the story said is an archaic type of mutual fund that vanished from the market two decades ago.

These plans require investors to pay half of their first year's contributions in sales charges. But if investors drop out early, they end up paying a very high portion of their investment as fees. Even those who don't drop out earn less than if they had avoided the high first-year fees, the paper said.

According to the Times, the National Association of Securities Dealers (NASD) and the Securities and Exchange Commission (SEC )have been investigating First Command's marketing since last summer but neither of the probes have thus far resulted in any formal disciplinary action against the company or its licensed agents.

Among some high-profile lawmakers asking for action include Senator Hillary Clinton, the New York Democrat, who said has asked Defense Secretary Donald Rumsfeld to initiate a Pentagon investigation into the matter, the story said.

The Times said the company declines to comment on the story although in earlier interviews with the paper, company executives defended their products as being appropriate for their customers.