(Reuters) - Major bitcoin corporate backer MicroStrategy Inc on Wednesday upsized a debt offering through convertible notes to $900 million, with the proceeds to be used for buying more of the digital currency. The company, whose Chief Executive Officer Michael Saylor is one of the most vocal proponents of bitcoin, said proceeds of the offering will be about $879.3 million. MicroStrategy said the notes have a 0% coupon rate. A zero coupon means the company does not face debt servicing costs. The company said on Tuesday it will borrow $600 million to buy more bitcoin, as the cryptocurrency surged past $50,000 in a rally fueled by wider acceptance among investors. Elon Musk’s Tesla Inc bought $1.5 billion of the currency earlier this month and major firms such as BNY Mellon, asset manager BlackRock Inc and credit card giant Mastercard Inc have backed certain cryptocurrencies in recent weeks. MicroStrategy, the world’s largest publicly traded business intelligence company, spent last year steadily amassing more bitcoin after making its first investment in August as the cryptocurrency soared in value. The company already owns close to 72,000 bitcoin, according to a regulatory filing on Feb. 8, acquired at an aggregate purchase price of $1.15 billion and an average price of about $16,109 per bitcoin. MicroStrategy’s bitcoin holding is valued at about $3.67 billion, based on Wednesday’s price of $51,721, according to a Reuters calculation. The company bought nearly 25,000 bitcoin for $250 million in August last year, when it made a foray into the digital currency. Saylor at the time called bitcoin an attractive investment asset, with more long-term appreciation potential than cash. MicroStrategy said last week it views its bitcoin coffers as long-term holdings and does not plan to regularly trade in the currency, hedge or enter into derivative contracts. (bit.ly/37gpzGw) (bwnews.pr/3s4YwpP)