NEW YORK (TheStreet) -- JPMorgan Chase (JPM) - Get Report doesn't want anymore of its people or profits going to Morgan Stanley (MS) - Get Report, Citigroup's (C) - Get Report global head of retail banking is about to get more responsibility and Goldman Sachs (GS) - Get Report upgraded Greenhill and Co.'s (GHL) - Get Report rating to buy on Thursday.

In a fight reminiscent of the feud between the twin sisters who wrote the Ann Landers and Dear Abby advice columns, JPMorgan is taking legal action to keep Morgan Stanley from poaching its talent and clients.

The New York bank filed lawsuits against six former executives who left for Morgan Stanley in February, seeking to stop them from taking clients with them, Bloomberg reports.

The two banks, once one and the same, were forced to split following the adoption of the Glass-Steagall Act in 1933, which forced the separation of investment and commercial banking operations. The repeal of Glass-Steagall in 1999 allowed investment banking and commercial banking to exist under one roof again. But by then the banks had diverged significantly.

Shares of JPMorgan closed down 0.5% at $68.67 while Morgan Stanley dropped 1.2% to $39.22.

Citigroup is combining its retail banking and mortgage operations and Jonathan Larsen, current global head of retail banking, will lead the division, Bloomberg reports. The change will take place immediately, according to a memo Thursday from Stephen Bird, CEO of the global consumer bank.

The change is one of many at the bank in recent months. Bird himself is relatively new in his role, having replaced Manuel Medina-Mora as head of the consumer bank in April.

"Banking with us should be radically simpler," Bird wrote in the memo. "We must accelerate our efforts to build a single, globally common business and intensify our focus on designing the future of banking."

Shares of Citigroup fell 0.8% to $56.19.

Goldman Sachs doesn't anticipate a slowdown in dealmaking activity, according to a report issued on Thursday by analyst Danial Paris. As such, the bank upgraded its rating on the stock of Greenhill & Co., a New York-based M&A advisory firm, to "buy."

To date, $1.6 trillion in mergers and acquisitions has been announced in 2015, Bloomberg reports, but not all of the deals have been completed. Still, Goldman Sachs sees more M&A activity on the horizon.

"We are only in year two of a five-year M&A growth cycle," Paris wrote.

Shares of Goldman Sachs slipped 0.8% to $212.73 while shares of Greenhill closed up 4.7% at $41.87.