State of Wisconsin Investment Board (SWIB) has divested $321M worth of BlackRock's Bitcoin ETF shares.SWIB was an early buyer of spot Bitcoin ETFs, setting a precedent for other U.S. states to follow.Even though SWIB increased its IBIT holdings to $107M at one point, it has now exited its position.Goldman Sachs has become the largest known IBIT holder globally, solidifying IBIT's dominance in the spot Bitcoin ETF market.