Excerpt - Sources: Grasso Ally Langone Mounting Bid for Archipelago Financier Kenneth Langone is mounting a rival bid to buy electronic trading platform Archipelago Holdings Inc. (AX), a move rich in Wall Street politics that threatens to derail its proposed union with the New York Stock Exchange, according to people familiar with the matter. The Home Depot Inc. (HD) co-founder and friend of former NYSE chief Dick Grasso quietly reached out to a number of Wall Street chief executives, asking them if they would be interested in participating in a counterbid for Archipelago. Mr. Langone, according to some of the...