Shares of Ideanomics Inc. /zigman2/quotes/208536109/composite IDEX +3.85% soared 64.9% in very active midday trading Monday, making them the biggest gainers on the Nasdaq Exchange, after the company focused on investing in disruptive technologies announced the doubling of its investment in California-based Solectrac Inc., which makes battery-powered electric tractors. Trading volume swelled to 189.4 million shares in recent trading, compared with the full-day average of about 11.7 million shares. Ideanomics said it invested an additional $1.3 million in Solectrac, which increases its ownership stake to 24%. Ideanomics had announced on Oct. 22 an investment of $1.3 million to buy the 14.7% stake in Solectrac. Ideanomics said the latest investment allows it to recognize its stake in Solectrac under the equity method of accounting under generally accepted accounting principles (GAAP). "We believe Solectrac has enormous potential and, given the uptick in both product inquiries and investment interest they are seeing, we exercised our rights to increase our stake so we can help Solectrac scale to meet anticipated market demand," said Chief Executive Alf Poor. The stock has now nearly tripled (up 196.8%) year to date, while the S&P 500 /zigman2/quotes/210599714/realtime SPX +0.31% has gained 10.4%.