Having revolutionized the business of buying stocks, Vanguard Group is now coming for currencies. The investing pioneer obsessed with lowering costs is testing a new way for asset managers to trade currencies and avoid big investment banks, according to a person familiar with the matter. The platform, based on the blockchain technology that powers Bitcoin, has been operational for two months and has handled some trades, said the person, asking not to be named because the project is private. If successful, the venture could shift power in the $6 trillion a day currency market that banks such as JPMorgan Chase & Co. ... (full story)