A stockbroker who worked at a Ronkonkoma investment company has been barred from the financial services industry under a consent agreement after ringing up almost $400,000 in markups, markdowns and transaction costs on unauthorized trades of a retiree’s Colgate-Palmolive stock, a regulatory body said.

The penalty is the harshest that the Financial Industry Regulatory Authority can assess, a spokeswoman for the agency said.

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In an agreement dated Feb. 28, FINRA accepted the settlement offer of the broker, Craig David Dima, who neither admitted nor denied the charges.

In September 2009, Dima joined Ronkonkoma-based K.C. Ward Financial, according to the settlement order. From 2010 to 2015, he made 82 trades involving about $15 million on the account of a 72-year-old retiree identified only as “RS,” who had worked for the maker of soaps and toothpaste for 28 years, according to the settlement.

To cover his tracks, Dima told RS that the trades were the result of human error or computer issues, according to the settlement.

RS paid fees, markups and markdowns — the price differential between the market price and the prices set by dealers when they trade for their own accounts — of about $376,000. Those markups and markdowns were deemed “excessive” by FINRA. The retiree also “was deprived of approximately $127,000 in dividend payments” as a result of the trades, according to the settlement.

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A call for comment to K.C. Ward Financial was not returned. Efforts to reach Dima by telephone were not successful.