Nobody wants to use the 'B' word, but a bubble is upon us, a growing number of market watchers are warning.

And it could pop sooner than many expect, Centricus Asset Management Fund Manager Ralph Jainz said Monday.

Assets like tech equities are becoming increasingly expensive while traditionally defensive stocks like healthcare, pharmaceuticals and telecoms are losing out.

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Nobody wants to use the 'B' word, but a bubble is upon us, a growing number of market watchers are warning.

And it could pop sooner than many expect, Centricus Asset Management Fund Manager Ralph Jainz said Monday, joining a long list of financial players casting doubt on the strength of the market's current bull run.

"Nobody wants to talk about this being a bubble. It's the greatest asset inflation bubble we have seen in 20 years," Jainz said during an appearance on CNBC's "Squawk Box Europe."

There is wide disagreement over whether markets have further to climb or whether we'll see a spectacular market correction. Investing titan Mark Mobius recently predicted an impending correction of up to 30 percent, while others see no cause for concern.

But assets like tech equities have hit their highest points ever this year, and because of this, Jainz explained, traditionally defensive stocks like healthcare, pharmaceuticals and telecommunications are losing out. And these are exactly where you'd want your money to be in the event of a downturn, which Jainz believes may be just a year away.

"Dispersion levels have been rising, people have been selling the losers to buy the winners," the fund manager said, describing stocks that were already expensive becoming more expensive — like those in tech — as buyers rush to those out-performers and in turn sell the underperformers.