Fear and sadness in Silicon Valley by Dan Primack @FortuneMagazine 7:35 AM EDT E-mail Tweet Facebook Linkedin Share icons Every couple of months I leave my small Massachusetts town — where most people still shop for their own groceries and drive their own cars — and head for the Bay Area. Suddenly, all of my cynicism and bubble worries are drowned out by the kind of unfettered optimism that only $1 billion valuations (on $0.00 earnings) can buy. But not today. Not this time. Since landing in San Francisco on Wednesday, I’ve met with an assortment of senior venture capitalists, bankers, entrepreneurs and crossover investors. All of them have, in one way or another, been involved with so-called ‘unicorn’ companies. As in the past, they are nearly unanimous in sentiment. The difference now is that their sentiment is fear. The past several years of raising too much, too high, too soon has run smack into a much more conservative investor ethos. Later-stage tech startups can still raise growth equity — and still lots of it — but not necessarily at the terms they were receiving just two months ago. “This shift is only five or six weeks old, so most companies haven’t felt it yet,” a senior tech banker explains. “But I know of many companies who raised money at $1 billion valuations last year that are now being told that, to raise money now, they need to take around $700 million or $800 million. Probably with some serious structure that protects investors, like ratchets, on top of it.” The reality is that record-high private market valuations have been driven by two things: Wall Street’s lust for growth at all costs, and relatively high tech multiples in the public markets (and, more specifically, applying the former to the latter). But a variety of macro economics factors (China, the inscrutable Fed, etc.) have cut public equity prices and moved the spotlight to unit economics, which means some pretty large biz model disruption for the disruptors. Moreover, many of the crossover investors fueling these big deals were playing primarily for IPO optionality, and the successful VC-backed tech IPO has become few and far between. No longer are they willing to have terms dictated to them when the endgame seems so much less certain, and particularly not based on ambitious internal growth projections that would never be provided to the public in filings or on earnings calls. To be clear, I don’t have data backing any of this up. As the banker said, it’s too new a phenomenon and, of course, there will be notable exceptions. Moreover, this isn’t to say that the bubble is popping so much as to argue that the ever-rising valuation peak is in the rear-view mirror for later-stage companies (it hasn’t yet trickled down to the seed-Series C world yet). What should be very interesting, of course, is how such companies do react once they need to fundraise. Do they accept the lower valuations in the private market and, if so, will they publicize their ‘new’ valuations as they publicized their old ones? Will they take the public plunge under this lower valuation regime — both for financing and future capital markets access — given that the easy money in private markets has slowed? Or will all of this eventually get corporate acquirers off the sidelines, after several years of griping that everything is too expensive to buy? Chances are that we’ll see all of the above. But that’s for later. For now, all I see is wistful sadness, like children at the end of summer vacation. All anyone really knows for sure is that hard work and more than a little uncertainty lies ahead. Get Term Sheet, our daily newsletter on deals and deal-makers.