Credit Suisse Group AG leaders are discussing replacing chief risk officer Lara Warner while sparing Chief Executive Officer Thomas Gottstein as they tally losses that could reach into the billions from the collapse of Archegos Capital Management, according to people briefed on the matter.

The bank is set to give investors an update on the Archegos fallout, including the fate of top executives such as investment bank chief Brian Chin, two of the people said. They also said the Swiss firm is planning a review of its prime brokerage business, which is housed in the investment bank.

“I think it is unfair at this stage to put this on Mr. Gottstein,” David Herro from Harris Associates, one of the bank’s top shareholders, said in a Bloomberg TV interview last week.  “He attempted and has been attempting to reorganize Credit Suisse, but Rome wasn’t built in a day. Unless we see evidence to the contrary, I think he is the right person to continue to lead the organization.”

A Credit Suisse spokesperson declined to comment.

Read more: How Credit Suisse is bracing for a stunning losses likely to run into the billions

The No. 2 Swiss bank stands as one of the biggest potential losers in the meltdown at Archegos, which could cost banks a collective $10 billion, JPMorgan Chase & Co. analysts have estimated. That came just weeks after the collapse of Greensill Capital, a lender that ran funds Credit Suisse offered to its asset-management clients.

The one-two punch has made Credit Suisse the worst-performing major bank stock in the world so far this year as a strong start for its investment bank business was overshadowed by the bank’s exposure to Greensill and Archegos, a New York-based family office.

The bank’s 1.5 billion Swiss franc ($1.6 billion) share buyback program is at risk of being paused for the second time — after first being stopped at the onset of the pandemic last year — and losses could put pressure on dividend payouts. S&P Global Ratings downgraded its outlook for the bank to negative from stable pointing to risk management concerns.

A hit to profit exceeding $5 billion would start to pressure on Credit Suisse’s capital position, according to JPMorgan. The Swiss regulator FINMA increased Credit Suisse’s requirements under its Pillar 2 buffer, after the bank warned it could incur a loss from winding down of the supply-chain finance funds linked to Greensill.

Here are the Credit Suisse leaders who will be at the center of the action in coming days and weeks:

Thomas Gottstein, chief executive officer

The surprise choice to take over in February 2020, following a spying scandal that drove out Tidjane Thiam, Gottstein previously led the bank’s business in Switzerland. When he got the job, he declared that it was “time to look forward,” But Credit Suisse’s troubles have only metastisized since then. 

First came a $450 million writedown on the bank’s stake in hedge fund York Capital and costs related to a longstanding legal case into residential mortgage-backed securities.

Then, Greensill’s supply-chain finance business blew up. The board of directors and regulators are looking into how Credit Suisse’s supply-chain finance funds, linked to the Greensill business, were sold to investors, including to its own wealth-management clients, and how the bank managed conflicts of interest and its business relationship with Greensill, Bloomberg News has reported. 

The Archegos episode raises questions about his handle on risk management, particularly since one of his first major initiatives was merging the risk and compliance divisions to streamline and improve risk decision making.

“Risk controls still are not where they should be,” Herro said. “Hopefully this is a wake-up call to expedite the cultural change that is needed in this company.”

Lara Warner, chief risk and compliance officer

With dual Australian-U.S. nationality and a career that’s ranged from equity analyst to investment bank chief financial officer, Warner has taken a less traditional route than many of her peers to the highest echelons of risk management and Credit Suisse’s executive board. She was the highest-profile member of Thiam’s inner circle to win a spot in Gottstein’s top ranks. Her promotion to risk and compliance chief came in the reshuffle that saw the two units combined.

She’s facing some of the same tough questions as Gottstein about risk-management practices and culture following her personal involvement in signing off on a loan to Lex Greensill in October.

In an area of banking run mostly by men steeped in risk models, her more business-focused approach hasn’t always gone down well, according to conversations with about half a dozen current and former employees who spoke on condition of anonymity. Several left after she took over, while those who stayed were challenged to engage more with the business, according to people who worked with her.

“In order for the good bits of Credit Suisse to blossom, you need to get rid of bad bits and that is the risk control which has plagued this company for the better part of a decade,” said Herro.

Brian Chin, CEO of the investment bank 

Along with Warner, Chin was a big winner in Gottstein’s shakeup last summer, when the trading head also won control of the investment bank after a merger of the two units.

His promotion — at least in part — was due to a turnaround in fortunes in global markets during the latter part of Thiam’s era. Now, his business is under intense pressure because of the Archegos losses.   

Emissaries from several of the world’s biggest prime brokerages tried to head off the chaos before the drama spilled into public view last Friday. Credit Suisse’s idea was to reach some sort of standstill to figure out how to unwind positions without sparking panic, according to people with knowledge of the matter.

That strategy failed, prompting banks to start selling. Credit Suisse and Nomura issued profit warnings on Monday. Later in the day, Gottstein and Chin held a call with shellshocked managing directors and other executives where they said the lender was still working to figure out the size of the hit and told bankers this was a time to pull together and not focus on the potential impact on pay.

Paul Galietto, equities trading head

Galietto joined Credit Suisse in 2017 after a stint at UBS Group AG and a two-decade run at Merrill Lynch & Co. He ran Credit Suisse’s prime brokerage unit before rising to lead the equities trading division two years ago.

Galietto has been tasked with helping the investment bank in its strategy of delivering more stable results while using less capital than the trading business historically has. While revenue has stabilized after a significant decline before Galietto’s arrival, the firm ranks well behind U.S. rivals it used to surpass.

The equities business posted a 6% increase in revenue last year as clients were active in response to the pandemic, but that paled in comparison to jumps of more than 30% at some major rivals. The bank told investors in December that it still ranked fifth in cash trading and its prime brokerage, led by John Dabbs and Ryan Nelson, was in the top four in each major region.

Urs Rohner, chairman

The Credit Suisse chairman, who has presided over one of the most tumultuous periods in Credit Suisse’s recent history during his 10-year tenure, steps down April 30, when Lloyds Banking Group Plc CEO Antonio Horta-Osorio takes over.  

Herro of Harris Associates, who called for him to resign in his standoff with Thiam over the spying scandal, has already singled him out in the wake of the Archegos disclosures.

Antonio Horta-Osorio, incoming chairman

The outgoing CEO of the U.K.’s Lloyd’s Banking Group Plc, he led the bank back to private hands following a 2008 nationalization. The Portuguese national transformed Lloyds in his decade-long tenure, turning it into one of the most efficient lenders in Europe amid thousands of job cuts.  

— With assistance by Marion Halftermeyer, Dale Crofts, Stefania Spezzati, Michael J Moore, and Jonathan Ferro