Alibaba Group’s (BABA) meteoric rise in its stock price has cost short sellers a lot of money and even prompted famed short Jim Chanos to throw in the towel on his bearish bet.

Chanos, the founder of Kynikos Associates, has been an outspoken critic of China’s largest e-commerce company, but he told CNBC this week he covered his short bet in January, reported Bloomberg. “I do have problems with Alibaba’s accounting. I still have problems with Alibaba’s accounting, but for the time being we’ve moved on,” he reportedly said. The investor still expressed concerns about the company’s business model and financial disclosures. He also pointed out that the company’s balance sheet is growing at a faster rate than the businesses, namely its logistics unit.

Those criticisms were dismissed by Joe Tsai, executive vice chairman of Alibaba, in a subsequent interview with CNBC, reported Barron’s. Tsai said Chanos doesn’t appear to understand the business or the digital economy in China. Chanos rose to fame when he forecasted the demise of Enron Corp. He has had short positions on Alibaba since November 2015, noted Bloomberg. Since then the stock has more than doubled and is up around 97% so far this year. (See also: Time to Buy Alibaba Bonds? BofA Merrill Thinks So.)

Skeptical of Success

The short seller isn’t the only one to raise concerns about Alibaba’s spending to branch into new markets as it aims to become the world’s fifth-largest economy. Last month Northern Trust Capital said it and rival Tencent (TCEHY) are risky, capital intensive bets that need to pay off to sustain the lofty stock prices. “The digital scale platform titans, such as Tencent, Alibaba and Facebook deserve premium ratings, but they will need to ‘grow’ into such ratings rather than skyrocket higher,” wrote Neil Campling, head of global technology, media, and telecom (TMT) research at Northern Trust Capital Markets, in a report to clients that was covered by MarketWatch. “For those stocks where there is a significant gap between the two metrics we wonder if we may see some pressure on stock prices in the short term.” That call came a few days before Alibaba reported fiscal first quarter results that blew past Wall Street views. (See also: Four Hedge Funds Buy Alibaba Ahead of Earnings.)

Overall revenue in the quarter increased 56% year-over-year, core commerce revenue jumped 58% and revenue from its digital media unit increased 30%. Annual active consumers on its e-commerce platforms grew by 12 million compared to last year’s fiscal first quarter while mobile monthly active users hit 529 million in June, an increase of 22 million compared to last year’s fiscal first quarter.

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