Thomson Reuters Corp. said Thursday it is adding $1 billion to its share buyback program, adding to the $500 million authorization announced in May. The company has repurchased about $231 million since resuming its buyback program last month. The news and financial data company said the buybacks will allow it to reduce the size of a planned $9 billion to $10 billion issuer bid/tender offer that the company is planning to make to all shareholders, tied to the sale of a 55% stake in its financial & risk division. Shares rose 1.1% premarket, but are down 9.3% in 2018 so far, while the S&P 500 has gained 3.7%.