In 2017 the total valuation of companies that have gone through YC will surpass $100 billion, absent a macroeconomic meltdown.

Judge at 31 December 2017. The condition is that there is no macroeconomic meltdown in 2017. If a widely recognized macroeconomic crisis occurred in 2017, the condition fails and the claim should be judged mostly false at most, with a note. Otherwise: True: YC or reliable reporting states that the combined valuation of YC alumni companies passed $100 billion during 2017. Mostly true: the figure reported for end-2017 or at the 2017 milestone is $100 billion or more, but the exact crossing date is unclear within the year. Mostly false: the $100 billion mark was passed only after 2017 (even early 2018), or the 2017 figure was close but below it (for example $85–99 billion). False: the reported 2017 total was well below $100 billion (under $85 billion).

Set before the research began.

1. E1 Y Combinator says its companies are on target for $100B total valuation Fast Company · 16 February 2017

   “It expects those companies to have a combined $100 billion valuation this year.”

2. E2 YC Summer 2017 Stats | Y Combinator Y Combinator · 21 August 2017 Own record

   “The total market cap of all YC companies is over $85B.”

3. E3 Timeline of Y Combinator - Timelines Timelines (issarice.com wiki) · 28 June 2019

   “YC reaches US$100 billion in market value for their portfolio of 1867 startups they’ve invested in since 2005.”

4. E4 YC Alumni Go Big: The 15 Most Valuable Y Combinator-Backed Startups Crunchbase News · 26 February 2018

   “According to its website YC companies have valuations that combined total more than $80 billion.”

The evidence gives only lower bounds for YC companies' combined valuation: over $85B in August 2017 [E2] and more than $80B per YC's website as cited in February 2018 [E4]. The $100 billion milestone in [E3] has no date. None of the evidence shows whether the $100 billion mark was passed during 2017 or after it.