TD Ameritrade Holding Corporation (Nasdaq: AMTD) and Scottrade announced on Monday that they have entered into a definitive agreement for TD Ameritrade to acquire Scottrade in a cash and stock deal valued at $4 billion dollars as of Oct. 24, 2016.

“The whole industry is under fee pressure,” Rich Ryffel told the St. Louis Post-Dispatch. Ryffel is a senior lecturer at Olin and a 30-year veteran of the securities business. “They want to get as much scale as they can,” he said.

According to the TD Ameritrade press release, “The transaction combines two highly complementary organizations with long histories of helping millions of people invest in their financial futures. For TD Ameritrade, the transaction adds significant scale to its retail business, extends its leadership in trading, and more than quadruples the size of its geographic sales force footprint.”

For the 12 months ended Sept. 30, 2016, TD Ameritrade and Scottrade, on a pro-forma combined basis, had:

• 600,000 average client trades per day

• $944 billion in total client assets

• 10 million funded client accounts

• $14 billion in margin balances

• $149 billion in cash balances