Williams Partners (NYSE:WPZ) is looking to expand its capital base. The partnership is issuing 21.5 million common units in an underwritten public flotation priced at $49.00 per unit. Additionally, sole underwriter Barclays has been granted a 30-day option to purchase up to an additional 3.225 million units.

Williams Partners said it plans to use the proceeds of the offering to retire debt, fund capital expenditures, and "for general partnership purposes." The issue is expected to close on August 7. Currently, Williams Partners has 413.9 million units outstanding, and its stock trades at $49.76 per unit.

The partnership reported its Q2 2013 results earlier this week. For the quarter, it posted a net profit of $256 million ($0.31 per unit), and fee-based revenues of $704 million. Those figures for Q2 2012 were $243 million ($0.29) and $684 million, respectively.