...TORONTO (S&P Global Ratings) Nov. 14, 2016--S&P Global Ratings today said its long-term ratings on Argo Group U.S. Inc. (AGUS; ###-/Stable/--), a wholly owned subsidiary of Argo Group International Holdings Ltd. (AGII), and financial strength ratings on AGUS' operating subsidiaries (A-/Stable) are unaffected by AGII's announced acquisition of Ariel Re (Holdings) Ltd. AGII today announced that it has entered into a definite agreement to acquire Ariel for about $235 million, financed through cash and debt securities. The acquired business primarily involves Ariel's re/insurance business through the Lloyd's syndicate, which will increase AGII's footprint in two of its business segments focused on international specialty and reinsurance. At the same time, the acquisition also increases the proportion of reinsurance business, a sector that is facing headwinds, and may add some volatility to the operating performance considering exposure to property and other severity risk. We believe the acquisition's...