Since its official launch in February 2014, the business communications app Slack has raised $US320 million in venture capital. It’s now worth $US2.8 billion, making it the fastest startup to reach a $US2 billion valuation.

A lot of Slack’s value is derived from its exceptional product, which is drawing in tens of thousands of new users every week. In February, it was adding $US1 million in annual recurring revenue every 11 days.

But Slack is also the beneficiary of one of the warmest VC markets ever.

In fact, Slack CEO Stewart Butterfield is the first to admit that the current market condition is what made it a lot easier to raise money. In a recent interview with Business Insider, he said, “I’ve been in this industry for 20 years and this is definitely the best time. It’s a wonderful, crazy environment for raising capital.”

So you would imagine Butterfield is praying for this tech boom to continue.

Not so much.

In an interview with CNBC on Thursday, Butterfield said a “giant crash” would actually help his company at this point.

“I wouldn’t wish this upon the world, but kind of the best thing that could happen from our perspective is a giant crash…Office space becomes cheaper, salaries become cheaper, buying advertising becomes cheaper, acquiring companies becomes more realistic,” Butterfield said.

Butterfield added he’s been looking for companies to acquire lately, but the price tags were just too high to swallow. “A VC-backed tech company these days is 50 million bucks. That’s kind of the floor, so it’s expensive,” he said.

Butterfield may not be the only with sticker shock. According to The Information, tech M&A declined in the first quarter of 2015. There were a total of 118 tech company acquisitions in the first three months of this year, while there were 134 in the previous quarter, and 144 in the year-ago period.

Although it’s unclear if the outsized startup valuations are contributing to this trend, there’s no question the cost of running a startup and acquiring one is reaching unprecedented highs. Real estate in Silicon Valley, for example, has gotten so ridiculous that even a six-figure earning software engineer finds it hard to live in the area.

But if anyone knows what it feels like to own a startup too expensive to buy, it would be Butterfield himself. He said during the Code conference this week that he’s received 8 or 11 acquisition offers from other companies, none of which obviously materialised.

He even told us back in August, after raising $US42 million at a $US500 billion valuation, that his company’s rich funding round “sends the message that if you want to acquire us, you probably can’t afford us.”

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