The Swiss bank's staunchest supporter is Harris Associates, but the U.S. mutual fund is nursing losses on its years-long investment. When will portfolio manager David Herro have had enough?

«There are some strong building blocks, and they just have to clean up the people who are responsible for accepting a culture that doesn't balance risk and return,» Harris' investment chief David Herro told «Bloomberg TV» overnight. He was asked by the financial broadcaster what it would take to offload a stake of just over five percent in Credit Suisse.

An as-yet undecipherable hit from Archegos' unwinding has sliced 5 billion Swiss francs ($5.3 billion) off the Swiss bank's market capitalization this week alone. The debacle follows the blow-up of a $10.1 billion line of supply chain funds co-managed with Greensill earlier this month. The wreckage imperils Credit Suisse's future, as finews.com wrote on Thursday.

Cultural Wake-Up Call

Harris Associates, a subsidiary of French asset manager Natixis, is Credit Suisse's second largest investor, after Qatar's sovereign wealth fund. Portfolio manager Herro, an experienced foreign investor with a fondness for the wealth management sector, has not done well with the position, which has shrunk to one-third its original value.

Nevertheless he's not ready to sell just yet: «We're not there with Credit Suisse. We think the building blocks are there, and hopefully this is a wake up call to expedite cultural change that's needed in this company,» Herro said.

Losing Swiss Showdown

The Chicago-based Herro lost a showdown with Credit Suisse Chairman Urs Rohner last year, when Harris backed ex-CEO Tidjane Thiam in a surveillance affair. «We didn't have enough Swiss support, I don't know why,» Herro told the broadcaster. 

Asked whether Harris has the support now given Greensill as well as Archegos, Herro said «I certainly think it's opened eyes up in Switzerland». His comments from amidst a raft of downgrades for Credit Suisse, most recently with Moody's lowering its outlook to negative, from stable.