Well Berkshire can convert now if they want, but they'd have to spend $5 billion to do so which is a lot for a $140 million dividend. Its very unlikely that they would do that because in my opinion its much more favorable to transfer the 6% BAC preferred to settle the cost of exercising the warrants. The BAC preferred may not be redeemed by Bank of America for 5 years due to the recent agreement but its my understanding that Berkshire retains the right to transfer the preferred stock to exercise its warrants. Of course, that would be transferring $300 million pretax for only $140 million in dividends so theres little incentive to do it for the time being. I think it would take a 50 cent dividend or redemption of the preferred stock to get berkshire to convert prior to 2021.