MicroStrategy Inc (NASDAQ:MSTR) shares are trading lower Tuesday after the company announced a proposed private offering of convertible senior notes. What Happened: MicroStrategy announced after the market close on Monday that it intends to offer $600 million worth of convertible senior notes due 2030 in a private offering to qualified institutional buyers. The company plans to grant the initial purchasers a 13-day window to buy an additional $90 million worth of the notes. MicroStrategy said it intends to use the net proceeds from the sale of the notes to buy more Bitcoin, as well as for gene…