The first of May is often an uncomfortable realization for some Americans: many of us, the author included, aren't exactly ready for beach season. 

Silicon Valley unicorns appear to be no different. Some of the world's largest and most highly-valued startups that completed, or are planning, 2019 initial public offerings spent this spring slimming down in anticipation of their big debut. 

Our data shows that at Pinterest ($PINTEREST) and Uber ($UBER), a drop in job postings could be matched to the same timeframe leading up to the company's IPO filing with regulators, as well as the offering to investors that typically follows a few weeks later.

Pinterest had nearly 150 jobs posted online a month before the news broke that it would go public - but the most recent tally of jobs posted is down more than 18%, to 121. The company made its public market debut in mid-April.

Then, there's the IPO many investors are eagerly anticipating - ridesharing titan Uber, which filed paperwork to IPO around April 11, according to reports. A month prior to the IPO paperwork landing with the SEC, our data shows Uber had about 2,210 job postings online. By the end of April, that figure fell more than 16%, to 1,850 listings. 

/"Postmates Job Openings

There are yet other unicorns that haven't yet made a public market debut, but are rumored to be considering public offerings. Postmates ($POSTMATES), according to our data, recently hit a peak for the number of jobs it has posted online. But, if that figure starts to dip, it could be a tell-tale sign bankers are whispering to the delivery startup's executives that they need to shape up financials in advance of a road show.