Pimco founder Bill Gross has been criticized for his management style.

Pimco’s corporate culture has suffered since the giant bond fund lost one of its top leaders, according to a report issued Tuesday.

Morningstar, an influential investment research firm in Chicago, said that the resignation of CEO Mohamed El-Erian in January raised a higher degree of uncertainty about the world’s largest bond manager.

Morningstar did not change the ratings on any of Pimco’s funds though. Morningstar rates funds via stars and they are based on performance and risk factors. A 5-star rating is the highest and 1-star is the lowest. Pimco’s flagship Total Return Fund (PTTRX ) currently has a rating of 4 stars from Morningstar.

A Pimco representative did not immediately respond to a request for comment.

Morningstar said reports of a falling out between El-Erian and Bill Gross, the founder of Pimco and current chief investment officer, can arguably be viewed as tabloid fodder. But the departure of El-Erian, along with several other top executives in recent years, has helped drive material changes in Pimco’s corporate culture.

The resignation of El-Erian, who was the heir apparent at Pimco, raises questions about who will take over once Gross steps down. The company appointed six new deputy investment officers in conjunction with El-Erian’s departure.

It also changes the make-up of Pimco’s investment committee. Without El-Erian, there is no longer a senior-statesman on the committee, which Morningstar says has the atmosphere of a pressure cooker.

It remains an open question whether the current Investment Committee members — several of whom are a bit less seasoned than their predecessors — will consistently voice their opinions and fuel the debate that has been crucial to Pimco’s past success, the report states.

In addition to El-Erian’s departure, Morningstar points to the decision by Chris Dialynas, a veteran Pimco executive and investment committee member, to take a sabbatical this year.

Dialynas’ loss is especially notable given his reputation as something of a ‘glass-half-empty’ kind of guy in contrast to — and as an important foil to — Gross, who sees himself as more of an optimist when looking at economic and investing landscapes, Morningstar states in its report.

Gross has been forced to defend his reputation after a report in the Wall Street Journal described the 69-year-old billionaire as difficult to work with at best, and borderline megalomaniac at worst.

The article suggests that El-Erian stepped down due to conflicts with Gross over management style.

Meanwhile, investors have been pulling money out of Pimco’s Total Return fund as the long-running bull market in bonds appears to have peaked last year.

The high-profile split with El-Erian has not helped matters. But Morningstar says Gross is uniquely suited to manage Pimco’s vast size, given his decades of experience at the $2 trillion fund.

Whatever the image that his latest personality tribulations have projected in the wake of El-Erian’s departure, there remain good reasons to believe he can persevere and his success persist, Morningstar says.

Gross is known for his colorful metaphors in monthly letters to investors and has been active on Twitter (TWTR ). In October, Gross used the social media platform to criticize activist investor Carl Icahn, who was pushing Apple’s (APPL ) management to use the company’s cash to reward shareholders.

In an interview with CNBC, Gross pushed back against the allegations in the WSJ story. Among other things, he said he encouraged his employees to form conga lines as a way to relieve stress.

Other than that, Gross has not openly discussed the circumstances surrounding El-Erian’s departure. As a side note, El-Erian opened a Twitter account Monday. We expect he’ll take the high road and won’t tweet about Pimco’s dirty laundry. Your move, Bill.