It seems like all the usual suspects, and a phalanx more, have weighed in on the bubble controversy. We have been cautioning about unreasonable valuations in subtle but rising tones for about nine months now. And while we still see great companies at reasonable valuations, the number of valuations in nosebleed territory continue to rise.

The valuation froth seems concentrated at the bookends of startup evolution. We’re seeing declining numbers of larger A rounds, falling IPO activity, and huge late stage rounds.

The overall market is stretched and is producing overly high valuations on high risk assets. Years of exceptionally low interest rates have driven returns on less “risky” assets to below zero in some cases. This has created a larger than sustainable interest in all classes of risk assets. Inexpensive money sloshed out of low and negative returns has flooded real estate, venture, estate art, and so forth.

Venture and growth stage technology companies have been a major beneficiary of easy money and the hunt for return. The relative outperformance of Web 2.0 names from 2008-2009 enhanced interest in all things web tech above other areas. Disruptive firms and technologies outperform during periods of rapid economic change and turmoil. We are clearly living through such a period, and that is a real and profound shaping influence that should not be ignored. Thus, it is an odd cocktail of good reasons, easy money, crowd following, and greed that’s pumping the air into today’s valuation bubble.

There seems to be a sense of “getting while the getting is good” from leading decacorns and this is ratcheting-up valuation, froth, and investor fear of missing out. As hundreds of millions are raised in round after round, several things have become clear. Leading startups and their advisors are grabbing piles of eager cash at heady valuations. There is an arms race for the biggest brassiest round, and the bar is rising fast. As an analyst, I find many of today’s multiples well into the risk return red zone.

These days, the late-stage game is seeing more players with deeper pockets and different valuation metrics than before. Larger institutions need larger deals to justify risk, “move the needle,” and cover costly overhead. Many of these players are new to the space and are focused on outperforming the valuations they have traditionally seen at or after an IPO. This is creating a rush by folks to allocate more to the pre-IPO round as opposed to the IPO and post-IPO trade. If this trend continues, it will undermine itself, so it’s something we should all continue to monitor. Thus far, we have not seen particularly weak IPO pricing or offer price support as a result.

In the early-stage world, startup funding has become a cultural and political phenomenon. Reality shows, conferences, incubators, accelerators, media coverage, university programs, and corporate venture teams designed to fuel young startups abound. And a new, more modern and permissive regulatory environment is being erected to support this ecosystem. With veteran leaders behind these companies and a growing population of angel investors, early-stage ventures are pulling in bigger rounds of funding. Those cashing out of the last great deal, including in the frothy territory, are plowing that money into the next great hope and the next greater hype. This is how all of these momentum runs operate.

The key is that folks are also investing in hard and expensive-to-build technologies that are in many cases really changing how we live. We see huge developments in food distribution, health monitoring, education technology, enterprise collaboration, and smart data science.

Several of the leaders in this space have huge valuations that we think are justified. Many companies have valuations they will struggle to grow into, though, and still others have little hope of ever filling out the enormous, expensive valuations they “achieved” a few rounds ago.

We see the rage around messaging apps and delivery services as emblematic of valuations way out on the skinniest of skinny branches. Ironically, the last great bubble ended with frothy excitement about an army of delivery services. Then again, that was back in the dark ages before smartphone apps dispatched drones.

In short, we are in some stage of what will be looked back on as a bubble. Nothing is ever labeled or agreed upon as a bubble until it has popped. In all bubbles there are reasonably priced assets sitting next to overpriced assets. It always was and always will be our job to find the compelling valuations and to humbly strive to know the difference.

Max Wolff is chief economist at Manhattan Venture Partners, and Santosh Rao is head of research at the firm.