* Marianne Lake to replace Doug Braunstein as CFO
* Braunstein to become a vice chairman
* Lake, an accountant, has worked in finance across bank
By David Henry
Nov 19 (Reuters) - JPMorgan Chase & Co on Monday named Marianne Lake, currently financial chief of its retail banking unit, to be chief financial officer, elevating a little-known executive to the senior ranks of the largest U.S. bank.
Lake, 43, will replace Doug Braunstein as CFO early next year, becoming one of the highest-ranking women on Wall Street, along with others such as Ruth Porat, the chief financial officer of Morgan Stanley.
Lake will answer directly to Dimon in her new job, reestablishing a reporting line for the job that Dimon had taken from Braunstein in July.
"I hope to be described as a great partner and someone who helped drive and develop the business," Lake said in a interview.
Braunstein, 51, a former investment banker, will become a vice chairman at JPMorgan and "focus on serving top clients," according to an announcement from the company.
JPMorgan Chase, roiled by $6.2 billion of trading losses from bad credit bets, has seen a series of management shake-ups in recent months.
In a reshuffle over the summer, Dimon named Michael Cavanagh and Daniel Pinto - both in their late 40s at the time - co-chiefs of commercial and investment banking.
A person familiar with the matter last month said any move by Braunstein would be his decision and was unrelated to the bad credit trades.
The reshuffles also come as Dimon grooms a younger group of executives at the bank. Both Cavanagh and Pinto are seen as prime candidates to succeed Dimon, 56, when he is ready to retire.
Lake has been the CFO for JPMorgan's retail branch systems since 2009. From 2007-09, she worked in JPMorgan's investment bank as global controller in finance and business management.
In Lake's previous roles, she saw the financial crisis up close as JPMorgan acquired investment bank Bear Stearns and then as the U.S. housing crisis battered JPMorgan's mortgage investments.
Lake has also known CEO Jamie Dimon since he came to the bank in 2004.
In the statement, Dimon said Lake "has developed an impressive breadth of knowledge and experience in finance across both our wholesale and our consumer businesses."
Lake, a chartered accountant, managed global finance infrastructure and control functions in JPMorgan's corporate finance group from 2004 to 2007. Before that, she was a senior financial officer for the company in the United Kingdom.
She also worked for PriceWaterhouseCoopers in London and Sydney before joining JPMorgan.
Lake is a citizen of both the United States and the United Kingdom, having been born to an American mother and a British father.