CVC was the private equity firm which parachuted in execs who softened up Halfords' suppliers in the run-up to June's flotation.
This softening up included slashing margins and requiring extended credit terms.
Today CVC sold 46 million shares, worth just under 300 pence apiece. At the time of the floation the shares were valued at 260p.
CVC partner Jonathan Feuer will remain as a director of the Halfords board.
The equity firm cannot sell any of the remaining 19.8 percent of Halfords shares for at least 60 days.