Planet Fitness, Newington, NH, is nearing a deal with a private equity firm.

According to a filing with the Federal Trade Commission, TSG Consumer Partners is the firm that is making the investment. The filing was first reported by Fortune.com.

Planet Fitness CEO Mike Grondahl confirmed to Club Industry in the November issue that his company was close to a deal with a private equity firm, whose name he withheld for confidentiality purposes. A source had told Club Industry that the company was a consumer-oriented private equity firm, which would match the description of TSG. Grondahl could not immediately be reached for comment for this story.

Planet Fitness would be the first fitness club in TSG’s portfolio, which consists of companies in the categories of apparel, personal care, food and beverage, restaurants and pet care. Current portfolio companies for TSG, which has offices in San Francisco and New York, include Cytosport, a developer of sports nutrition products, and Neuro, a functional beverage line that supports healthy and active living. Other companies that TSG has invested in include Vitaminwater, Met-Rx Nutrition and Smart Balance Foods.

Pierre LeComte, a managing director at TSG, is leading the transaction, according to the Fortune.com report. LeComte could not immediately be reached for comment.

Planet Fitness, which had been in the Top 10 of Club Industry’s Top 100 Clubs list for the past three years, chose not to be on the list this year. In 2011, Planet Fitness had total net revenue of $136.4 million compared to total net revenue of $92.3 million at the end of 2010, according to its Franchise Disclosure Document (FDD). Net income attributable to members of Planet Fitness Holdings LLC was $26.9 million in 2011 compared to $17.7 million in 2010.

Planet Fitness reported in its FDD that it had 520 clubs at the end of 2011, a jump from 390 clubs at the end of 2010 and 312 clubs at the end of 2009. Of the 520 clubs in 2011, 453 were franchised clubs.

In 2010, Planet Fitness was close to finalizing a deal with Goode Partners, New York, but that deal fell through.