Wells Fargo’s board said Monday that it would claw back an additional $75 million in compensation from the two executives on whom it pinned most of the blame for the company’s sales scandal: the bank’s former chief executive, John G. Stumpf, and its former head of community banking, Carrie L. Tolstedt.

In a scathing, 113-page report that made it clear that all the warning signs of the problem had been glaring, the board released the results of its six-month investigation into the conditions and culture that prompted thousands of Wells Fargo employees to create fraudulent accounts in an effort to meet aggressive sales goals.

The report, compiled by the law firm Shearling & Sterling after interviewing 100 current and former employees and reviewing 35 million documents, said that it was obvious where the problems lay. Structurally, the bank was too decentralized, with department heads like Ms. Tolstedt given the mantra of “run it like you own it,” and given broad authority to shake off questions from superiors, inferiors or lateral colleagues.

So many suspicious things should have added up, the report said: People were not funding — or putting money into — their new accounts at alarming rates. Regional managers were imploring their bosses drop sales goals, saying they were unrealistic and bad for customers.

Particularly in Arizona and Los Angeles, where this toxic culture was the most pronounced, managers explicitly told subordinates to sell people accounts even if they did not need them.

Because of the bank’s decentralized structure, the problem went unnoticed for a long time. When it finally came to light — thanks in part to a news report in The Los Angeles Times — the bank was slow to take action. Ms. Tolstedt, who ran the community bank — Wells Fargo’s term for the branch network — was told to fix the problem that she had created.

Her department saw itself as a “sales organization, like department or retail stores, rather than a service-oriented financial institution,” the report said. Further, Ms. Tolstedt was said to have kept hidden the true number of people who were fired for setting up false accounts. Her report to the board in October 2015 “was widely viewed by directors as having minimized and understated problems at the community bank,” the report said.

The board came away believing that only 230 employees had been terminated for acting unethically. The company had actually fired 5,300 over a five-year period — something the board only learned in September, after Wells Fargo announced that it would pay $185 million in penalties and fines to settle lawsuits brought by federal regulators and the Los Angeles city attorney over its creation of as many as two million sham accounts in the names of real customers.

Mr. Stumpf — who had a long and warm professional relationship with Ms. Tolstedt and was inclined to trust her and let her manage on her own — was warned as early as 2012 about “numerous” customer and employee complaints about the company’s sales tactics, but ignored growing evidence that the problem was pervasive, the board said in its report.

Much of the pressure-cooker climate stemmed from Ms. Tolstedt, according to the report, who led Wells Fargo’s community bank for eight years before retiring last year. The report casts her as a powerful and insular leader who focused obsessively on sales targets and turned a blind eye to signs that some managers and employees were cheating to meet them.

“She resisted and rejected the near-unanimous view of senior regional bank leaders that the sales goals were unreasonable and led to negative outcomes and improper behavior,” according to the report, which was commissioned by a committee of Wells Fargo independent directors.

Timothy J. Sloan, who succeeded Mr. Stumpf as chief executive, was largely exonerated by the report, despite the fact that he was also a career Wells Fargo executive. As president and chief operating officer, he became Ms. Tolstedt’s immediate supervisor in November 2015. At that point, the report said, he “assessed her performance over several months before deciding that she should not continue to lead the community bank.”