Facebook's long-awaited IPO filing is lifting shares of freshly minted public Internet companies, including recent laggards Zynga and Groupon.
Zynga Inc.'s business depends on Facebook's growth. Facebook's filing revealed 12 percent of the social-networking giant's fast-growing revenue comes from the maker of addicting games such as CityVille and Mafia Wars.
Zynga shares are up 16 percent in midday trading Thursday.
Daily deals site Groupon Inc. shares are adding 7 percent, while jobs networking site LinkedIn Corp. shares move up 6 percent, even though their revenues aren't tied to Facebook.
All three companies made their stock market debuts last year. Only LinkedIn's shares have traded consistently above their IPO price.