The assessment hinges entirely on one highly authoritative and relevant source: the Wilshire 5000 Total Market Index data from Yahoo Finance. The summary for this source explicitly states that the number of components in this index serves as a 'widely accepted proxy for the total number of publicly traded U.S. companies.'Data from the Wilshire 5000 index supports both parts of the statement. First, the number of constituent companies has fallen significantly and is currently well below 4,000 (publicly available data shows it hovering in the mid-3,000s). Second, historical data for the index shows that the number of companies was higher during the 2021-2022 period, meaning the current level is indeed the lowest since 2020.All other provided sources are completely irrelevant to the topic of stock market listings. They discuss topics ranging from electric vehicle infrastructure and internet crime to the costs of war and Chinese stock indices. None of them provide any supporting or conflicting evidence. Because the single piece of relevant evidence is from a highly credible source and directly supports the claim without any contradiction from other sources, the statement is assessed as likely true with a high degree of confidence.