Pimco's Gross has had a tough time: Friend

Why I returned to Pimco: McCulley

Strains at global investment firm Pimco persist more than six months after the abrupt January resignation of previous co-chief executive Mohamed El-Erian, The Wall Street Journal reports.

Founder Bill Gross, the face of a firm that manages $1.97 trillion and its star investor, has threatened to quit more than once since El-Erian's March departure, sources tell the paper.

It's been a tough time for Gross, Pimco's chief economist Paul McCulley said in an interview on CNBC's "Squawk Box" on Tuesday. "I've known Bill Gross almost a quarter century." But McCulley asserted the mood at the firm is positive.

Bill Gross
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That assessment seems to contradict the Journal, which also said that a group of Pimco senior executives have become so concerned about Gross's dealings with the media that they warned him to stop making public comments. (Read the full WSJ article here.)

McCulley—who came back to Pimco in the spring to bolster the executive ranks after retiring in 2010—said Gross did not have to twist his arm to return. "Pimco is in my blood, my DNA," he said.

"Pimco had been going through some difficult times earlier this year. I spent time with Bill personally as a friend. Out of that discussion came the idea maybe we can find a space that works on both sides of the equation," McCulley said. "So there was no begging going on."

—By CNBC's Matthew J. Belvedere. Staff from @CNBCWorld contributed to this report.