June 8 (Reuters) - MicroStrategy Inc, a major bitcoin corporate backer, has increased the size of a junk-bond sale to help buy more bitcoin, now targeting $500 million, Bloomberg News reported on Tuesday. The company, which initially had planned to issue $400 million of the debt, is offering a yield of between 6.125% to 6.25% on the secured offering, the report here said, citing a person familiar with the matter. MicroStrategy did not immediately respond to a Reuters request for comment. This comes a day after the world’s largest publicly-traded business intelligence company said it planned to raise $400 million through senior secured notes due 2028 in a private offering and use the net proceeds from the sale to buy more bitcoin. The company spent the last year steadily amassing more bitcoin after making its first investment in August as the cryptocurrency soared in value. It has since made multiple purchases of the digital currency. (Reporting by Akanksha Rana in Bengaluru; Editing by Shailesh Kuber) Our Standards: The Thomson Reuters Trust Principles.