Ray Dalio, the billionaire founder of the world’s largest hedge fund, Bridgewater Associates, likes to say that one of his firm’s core operating principles is “radical transparency” when it comes to airing employee grievances and concerns.

But one employee said in a complaint earlier this year that the hedge fund was like a “cauldron of fear and intimidation.”

The employee’s complaint with the Connecticut Commission on Human Rights and Opportunities, which has not been previously reported, describes an atmosphere of constant surveillance by video and recordings of all meetings — and the presence of patrolling security guards — that silence employees who do not fit the Bridgewater mold.

Hedge funds tend to be a highly secretive bunch, yet even within their universe Bridgewater stands out. The allegations, as well as interviews with seven former employees or people who have done work for the firm and a filing by the National Labor Relations Board, open a window into the inner workings of a $154 billion company that, despite its mammoth size, remains obscure. The firm is governed by “Principles” — more than 200 of them — set out in a little white book of Mr. Dalio’s musings on life and business that some on Wall Street have likened to a religious text.