Shares of Williams Partners L.P. (NYSE:WPZ) saw unusually-strong trading volume on Monday following a dividend announcement from the company,AnalystRatings.NET reports. Approximately 3,539,725 shares were traded during mid-day trading, a decline of 10% from the previous session’s volume of 3,927,790 shares.The stock last traded at $23.27 and had previously closed at $21.45.