I have looked at and own the warrants for BAC and WFC. I have reviewed the prospecti for each of these companies. I haven't looked further into warrants from other US banks. Part of the reason for this is that I have followed both companies since at least the credit crisis and have used their stores everywhere over the years.
The warrants allow me to buy BAC at 13.30. So for an average of about $6.50 so far I get to buy BAC some time by January 2019 for 13.30. Right now the break even price would be 13.30 + 6.50 = 19.80. I would recoup some money with the stock price somewhere between $14.00 and the 19.80.
Here are the problems I see with investing in BAC, warrants or common:
1) It is not really clear, and in fact, nearly incomprehensible, as to what may still be lurking on their balance sheet.
2) The stock could implode due to bad banking practices as in observation 1)
3) The bank could be forced into asset sales to bolster its balance sheet at some point in the future reducing its book value.
4) Regulation could wipe out profitability for years going forward.
5) As per number 1 - BV could be vastly inflated due to toxic waste on the balance sheet.