Will startup valuations change given rising antitrust concerns?

The United States has, over the past few decades, been extremely lenient on antitrust enforcement, rarely blocking deals, even with overseas competitors. Yet, there have been inklings that things are changing. Yesterday, we learned that Visa and Plaid called off their combination after the Department of Justice sued to block it in early November. We also learned a week ago that shaving startup Billie would end its proposed acquisition by consumer product goods giant P&G after the Federal Trade Commission sued to block it in December.

Visa will not acquire Plaid after running into regulatory wall

Many, many, many other deals of course get through the gauntlet of regulations, but even a few smoke signals is enough to start raising concerns. That new calculus is even before we start to look at the morass of reforms being proposed around antitrust in Washington DC these days, nearly all of which - on a bipartisan basis - would create stricter controls for antitrust, particularly in critical technology industries and information services.

So, what's the valuation prognosis for startups these days given that one of the most important exit options available is increasingly looking fraught?