Bond king Bill Gross is not known for his sunny predictions for the markets. But he took his pessimism to a new level in his latest monthly outlook.

He thinks that big banks are doomed.

Gross, formerly the head of bond powerhouse Pimco and now a fund manager at Janus (JNS), wrote that the combination of tougher rules and low/negative interest rates mean that bank stocks will be no more exciting than boring utilities for years to come.

He pointed to the collapse in the stocks of global banking giants Citigroup (C), Bank of America (BAC), Credit Suisse (CS), Deutsche Bank (DB) and Goldman Sachs (GS) since their 2007 peaks -- and warned that they may never get back to those lofty levels.

"Banking/finance seems to be either a screaming sector ready to be bought or a permanently damaged victim of write-offs, tighter regulation and significantly lower future margins. I'll vote for the latter," he wrote.

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Gross almost seemed to be writing an obituary for the financial system -- and capitalism for that matter. (Perhaps he's seen "Mad Max: Fury Road" one too many times?)

"Capitalistic initiative married to an ever expanding supply of available credit has facilitated economic prosperity much like the Sun has been the supply center for ... life's sustenance," he said, adding that "finance itself is burning out like our future Sun."

Tell us how you really feel, Bill.

His advice to investors? Don't be tempted by seemingly cheap bank stock valuations.

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He's also bearish on life insurers such as Prudential (PRU), Hartford (HIG) and MetLife (MET) because they depend on big returns from their investment portfolios to help fund their coverage costs.

"All of these insurers whether it be for life, accident, or storm damage, cannot cover claims as conveniently as they could in the past, because they can't earn as much on their bonds and stocks," he said.

He blamed central bankers around the world for creating this problem. The Federal Reserve kept interest rates near zero for eight years. The European Central Bank and Bank of Japan now have rates in negative territory.

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And this doesn't just hurt people with money in the stock and bond markets. It's bad news for anyone putting their cash in the bank with the hopes of generating any return on their deposits.

"The damage extends to all savers; households worldwide that saved/invested money for college, retirement or for medical bills. They have been damaged, and only now are becoming aware of it. Negative interest rates do that," he wrote.

Someone might need to give Gross a hug -- although he did end his outlook on a slightly more hopeful note.

"The Sun still comes up every morning but at different times according to the season. Summer, for our credit based financial system, is past and a shorter winter-like solstice is in our future," he wrote.

Oh, who am I kidding? That's not cheery at all!