TORONTO (Reuters) - Hedge funds have raised their bets against Canadian silver-mining stocks, January short-selling data from a market regulator showed, while the miners’ shares and silver itself rose sharply due to buying by retail investors. FILE PHOTO: An employee places ingots of 99.99 percent pure silver on a cart at the Krastsvetmet non-ferrous metals plant, one of the world"s largest producers in the precious metals industry, in the Siberian city of Krasnoyarsk, Russia September 22, 2017. REUTERS/Ilya Naymushin A social media-driven buying spree lifted silver to an eight-year high on Monday, spurred by posts on the same Reddit message board behind last week’s frenzied buying of GameStop Corp and other shares. But the rally later cooled on doubts about the ability of retail traders to move prices in a bigger, more liquid commodities market. “The Reddit-fueled trader is learning that ... the silver market is much bigger than some of the small cap stocks they have been trading,” said Edward Moya, senior market analyst at OANDA. ADVERTISEMENT Between Thursday and Monday, Toronto-listed First Majestic Silver Corp and Pan American Silver Corp soared 60.5% and 30.7%, respectively. Wheaton Precious Metals, Fortuna Silver Mines and Silvercorp Metals Inc all had double-digit gains over the same time period. The big rally drew the attention of short sellers who increased their bets on silver stocks to fall, indicating that hedge funds believe the rally is nearing an end. Short trades as a percentage of total traded volume for First Majestic rose to 28.5% for the second half of January, up from 12.8% in the first half of the month, Investment Industry Regulatory Organization of Canada (IIROC) data showed on Monday. ADVERTISEMENT Short positions in Pan American rose to 35.9%, from 3.3%, over the same period, while Fortuna Silver Mines saw an increase to 36.6% from 2.2%, and Silvercorp Metals Inc to 23.1%, from 1.4%. Hedge funds tend to bet a company share price will fall by borrowing a stock from an institutional investor, such as a pension fund, and selling it back at a lower price when the company dips in value, pocketing the difference. Reuters reported Monday that Mexico’s government plans to seek more than $500 million from First Majestic Silver as part of an ongoing tax dispute. Reporting by Maiya Keidan and Jeff Lewis; Editing by Cynthia Osterman