Looking at the universe of stocks we cover at Dividend Channel, on 5/20/15, Spok Holdings Inc ( SPOK) will trade ex-dividend, for its quarterly dividend of $0.125, payable on 6/25/15. As a percentage of SPOK's recent stock price of $17.37, this dividend works out to approximately 0.72%, so look for shares of Spok Holdings Inc to trade 0.72% lower — all else being equal — when SPOK shares open for trading on 5/20/15.Below is a dividend history chart for SPOK, showing historical dividends prior to the most recent $0.125 declared by Spok Holdings Inc: In general, dividends are not always predictable; but looking at the history above can help in judging whether the most recent dividend from SPOK is likely to continue, and whether the current estimated yield of 2.88% on annualized basis is a reasonable expectation of annual yield going forward. The chart below shows the one year performance of SPOK shares, versus its 200 day moving average: Looking at the chart above, SPOK's low point in its 52 week range is $12.93 per share, with $21.73 as the 52 week high point — that compares with a last trade of $17.34. According to the ETF Finder at ETF Channel, SPOK makes up 2.94% of the iShares U.S. Telecommunications ETF ( IYZ) which is trading higher by about 0.2% on the day Monday. In Monday trading, Spok Holdings Inc shares are currently trading flat on the day.