Strong Debut for Shares of Hilton and Aramark The hotel business is back, at least judging from Wall Street's reaction to Hilton Worldwide's stock on its first day of trading on Thursday. Shares in Hilton were more than 8 percent higher at midday, with the stock trading at $21.66, up $1.67. The hotel chain is one of the largest companies to go public this year and a main player in the hospitality industry, with brands ranging from the budget Hampton Hotels to the luxury Waldorf-Astoria in Manhattan. But its strong debut probably could not have been predicted a short time ago. The company went private in a $26 billion deal with the Blackstone Group in 2007 at the height of the takeover era. But not long afterward, the economy collapsed and the travel business along with it. Blackstone focused on cutting the company's debt and, as the economy recovered, Hilton's revenue recovered along with it. Hilton priced its initial public offering on Wednesday at $20 a share, just above the midpoint of its expected range, giving Blackstone an initial paper profit of $8.5 billion. Hilton is among a slew of companies backed by private equity firms to pursue I.P.O."s as the private equity firms have taken advantage of the booming stock market to sell their holdings. On Thursday, shares in the Aramark Holdings Corporation, another company backed by private equity, had a strong debut in the market. Aramark had also priced its shares at $20, but that was the low end of the expected range. Still, shares in the company, an operator of cafeterias and concession stands across the country, were up nearly 10 percent at midday, at $21.97. In contrast to Hilton, whose owner intends to retain a significant stake in the company, Aramark's owners - including the buyout arm of Goldman Sachs and the investment firms THL Partners and Warburg Pincus - planned to sell some of their holdings.