Looking at the universe of stocks we cover at Dividend Channel, on 5/15/13, BOK Financial Corp. ( BOKF) will trade ex-dividend, for its quarterly dividend of $0.38, payable on 5/31/13. As a percentage of BOKF's recent stock price of $64.96, this dividend works out to approximately 0.58%, so look for shares of BOK Financial Corp. to trade 0.58% lower — all else being equal — when BOKF shares open for trading on 5/15/13.Below is a dividend history chart for BOKF, showing historical dividends prior to the most recent $0.38 declared by BOK Financial Corp.: In general, dividends are not always predictable; but looking at the history above can help in judging whether the most recent dividend from BOKF is likely to continue, and whether the current estimated yield of 2.34% on annualized basis is a reasonable expectation of annual yield going forward. The chart below shows the one year performance of BOKF shares, versus its 200 day moving average: Looking at the chart above, BOKF's low point in its 52 week range is $50.89 per share, with $65.45 as the 52 week high point — that compares with a last trade of $64.96. According to the ETF Finder at ETF Channel, BOKF makes up 1.63% of the KBW Regional Banking Portfolio ETF ( KBWR) which is trading lower by about 0.1% on the day Monday. In Monday trading, BOK Financial Corp. shares are currently up about 0.1% on the day.