LA Times writer Joseph Menn sheds some light on why private equity firms might not be interested in buying Knight Ridder, parent of the Mercury News, Contra Costa Times and Palo Alto Daily News group. Reuters reported last night that one of the three private investment groups looking at KR said it won’t bid on the newspaper chain, and the other two are getting cold feet. Menn, in a report this morning, explained that the investment firms might be losing interest because, as non-newspaper companies, they wouldn’t be able to combine corporate jobs with those of an existing newspaper chain, eliminating one area of cost cutting. Analysts also told Menn that tax laws would make it difficult for firms to resell individual papers for a substantial profit.