Apple Inc. /zigman2/quotes/202934861/composite AAPL +1.20% Chief Executive Tim Cook warned President Donald Trump at dinner Friday that tariffs could hurt his company, Trump said Sunday. Speaking to reporters before boarding Air Force One in Morristown, N.J., Trump said Cook argued that U.S. tariffs on Chinese goods would give its rival, South Korea's Samsung Electronics Co. /zigman2/quotes/209800866/delayed KR:005930 -0.50% , an advantage, since it would not be subject to the same restrictions as Apple. "I thought he made a very compelling argument, so I'm thinking about it," Trump told reporters. Trump has threatened to impose 10% tariffs on $300 billion of Chinese goods scheduled to begin in two stages, on Sept. 1 and Dec. 15. Apple shares are up 31% year to date, compared to the S&P 500's 15% gain.