Virgin Group Ltd. said it plans to buy back the 37% of the company’s shares held by the public. The London-based entertainment conglomerate, which went public with much fanfare just two years ago, is offering $2.38 a share, the price at which the stock was first offered in November, 1986. The buyback price was above Monday’s closing price of $2.16. The offer values Virgin Group--which includes Virgin Records but not Virgin Atlantic Airways--at $422 million. Chairman Richard Branson and other directors have formed a firm called Glowtrack Ltd. to execute the buyback.