Olaplex Holdings Inc., a maker of hair products, has filed for an initial public offering, according to a filing late Friday. Private-equity Advent and other funds bought Olaplex in January 2020. The company filed to sell $100 million worth of stocks, although that amount is often a placeholder used to calculate filing fees. Olaplex listed sales of $270 million in the six months ended June 2021, up from $100 million in the year-ago period. It earned $95 million in the period, contrasting with losses of $22 million a year ago.