The FD newspaper, which also received a copy of the letter, published sections in which the authors ask for "whistleblower status" to air their grievances, which also include "integrity" concerns.

ABN said in its response that the bank wasn't sure the letter was actually written by employees and it was not clear why they would communicate by anonymous group letter rather than the bank's internal communications, which include whistleblower protections.

Former ABN chairwoman Olga Zoutendijk was forced out nine months ago over differences about her "leadership style".

Zoutendijk, an outsider hired from Standard Chartered, pushed for the early departure of former CEO Gerrit Zalm, a former finance minister deeply embedded within the country's ruling elite.

The Dutch government retains a 56 percent stake in ABN after its nationalisation during the 2008 financial crisis.

Zalm left a year before his term expired in 2017, followed by Zoutendijk herself.

New CEO Kees van Dijkhuizen was promoted from CFO and said that calm had been restored.

According to the FD report, the managers are concerned about the bank's lack of vision.

Zoutendijk had pushed for ABN's investment banking arm to do more business abroad, but in the letter managers complain those plans have been rolled back under Van Dijkhuizen and new chairman Tom de Swaan, a former member of the country's central bank.

ABN's current strategic vision is to remain a profitable Dutch-focused bank and to grow its private banking business in Northwest Europe.

This month ABN reported a third quarter net profit of 725 million euros ($830 million), up from 673 million a year earlier.

(Reporting by Toby Sterling; editing by Gopakumar Warrier and Jason Neely)