MicroStrategy (MSTR)

This company can be considered a BTC-ETF, on Tuesday 7th December it plans to offer $400 million worth of convertible bonds to raise funds to purchase more bitcoin. Proceeds from the private offering will be invested in the cryptocurrency "pending the identification of working capital needs," the company said.
As of December 4, 2020, MSTR held approximately 40,824 bitcoins that were acquired at an aggregate purchase price of $475.0 million.