Big Wall Street investment banks have missed out on a $26bn deal to combine two US brokerages that will create a wealth management giant with more than $5tn in assets.

Credit Suisse, the Swiss bank, PJT Partners, the New York-based boutique investment bank, and Sandler O’Neill & Partners, the New York-based specialist financial services bank, have emerged as the key advisers on Charles Schwab’s acquisition of brokerage rival TD Ameritrade. The all-share deal, valued at roughly $26bn, was announced today.