Tencent Holdings Ltd. 700, -0.38% amassed a 5% stake in electric carmaker Tesla Inc. TSLA, +4.42% in March, according to a filing with the Securities and Exchange Commission on Tuesday. The Hong Kong-based Internet company said it bought about 8.2 million shares in an offering and on the open market for about $1.8 billion. Tesla shares jumped 3% premarket after the filing was published, and are up 26% in the year so far, while the S&P 500 SPX, -1.11% has gained 4.6%.