The management of Wolverine Worldwide told the Goldman Sachs Retail Conference last month that sales to international accounts have tripled to 21 percent of total sales volumes for its “Boston brands” - Saucony, Sperry, Stride Rite and Keds - since it added them to its portfolio three years ago. Wolverine, which is scheduled to report its third-quarter results on Oct. 20, also said that foreign currencies will continue to impact its profitability through the first quarter of 2016. Product costs are affecting gross margins, but they are slightly mitigated by lower commodity prices. Operating margins are being pulled down by pension expenses this year, and this will continue in 2016. The company's three-year incremental investment plan, which calls for $100 million in additional expenses over the period, will accelerate in 2016 as compared to 2015 levels.