A definitive agreement to this effect has been signed between the companies.
As per the agreed terms, Piper Jaffray will pay $91m in cash and $48m in restricted stock for 100% of Simmons.
Based in the US, Simmons is an independent investment bank specializing in the energy industry including energy services & equipment, exploration & production, midstream and downstream.
With over 170 investment banking, sales & trading, equity research and private equity professionals, Simmons has executed over 830 strategic advisory transactions, over 330 private and public financings, totaling $260bn.
Simmons also manages two private equity funds in the UK.
Piper Jaffray investment banking global co-head Scott LaRue said: "This is a milestone transaction as we meaningfully increase the firm’s investment banking footprint. Expanding into the energy sector has been a long-term goal for us and we are pleased to have found the ideal partner to fulfill this strategy.
"We look forward to combining our broader product suite with Simmons’ sector expertise, unmatched reputation and extensive relationships to build on the firm’s long history of success."
The acquisition will help Piper Jaffray in achieving its goal of generating $500m in annual investment banking revenue.
With offices in the US and in London, Zurich and Hong Kong, Piper Jaffray offers asset management products and services through three separate investment advisory affiliates including Advisory Research, Piper Jaffray Investment Management and PJC Capital Partners.