Loomis, Sayles & Co. sued Citigroup Inc., alleging the bank caused more than $70 million in losses while executing two separate trading orders that swamped the market. The Boston-based investment firm says Citigroup’s global markets unit was serving as its broker in the purchase of almost 800,000 shares of Shopify Inc and sale of more than 5 million shares of Colgate-Palmolive Co. Despite being instructed to execute the trades in a manner that wouldn’t impact daily market prices, the bank allegedly placed the orders into an illiquid closing auction at the end of the day, on March 18. Citigroup “failed to conduct any ... (full story)