So far in 2010, 328 companies in the U.S. have been the target of PE-backed add-on deals, according to the PitchBook Platform. 291 of those deals have already been completed, while the remaining 37 are still in play. Last year, there were 336 add-ons with 254 completed by this point of the year, meaning 2010 is surpassing last year in terms of deal activity. For both years, PE-backed companies have added on more in B2B Products and Services than in any other industry. B2B accounted for 39.6% of the add-on deals in 2009 and 32.1% in 2010 YTD. Similarly, Healthcare ranked second in both 2009 and 2010 YTD with 15.8% and 17.3%, respectively. Since the beginning of 2009, the PE investors who have backed the most add-ons include The Blackstone Group (22 deals), Parthenon Capital Partners (15), The Carlyle Group (14), Kohlberg Kravis Roberts (11) and The Riverside Company (10).