Number of SaaS B2B Companies
While there is not enough publicly available data to answer your question, I was able to find a list of the top 8,777 Enterprise SaaS businesses (through Cardin Partners, a technology M&A advisory firm that tracks 25,000 enterprise SaaS businesses), of which 3,906 are in the United States. Additionally, Cardin provides an analysis of broader industry trends, such as the shift to artificial intelligence, market automation, and customer acquisition.
Below you'll find an outline of our research methodology to better understand why the information you've requested is publicly unavailable, as well as a deep dive into our findings.
An extensive search of the public domain revealed that the data that does exist precompiled is not specific enough. Given the fact that federal statistical agencies identify industry data by the North American Industry Classification System codes, a search revealed that there is no NAICS code for SaaS companies. Any statistics from government websites would group this entire category together, including all companies that primarily offer Data Processing, Hosting, or Related Services (code 518210). Therefore, any federally-sourced statistic wouldn't be specific enough to answer the question posed.
Additionally, a rough estimate cannot be calculated, due to the fact that there isn't any data about the percentage of Data Processing, Hosting, or Related Services companies that are SaaS, B2B, or both, and no data about the percentage of B2B businesses that are also SaaS businesses.
Though I wasn't able to find the answer to your question, I did find a technology M&A advisory firm that tracks 25,000 enterprise SaaS companies, and discloses their Global Enterprise SaaS 10k List (Cardin Partners). The list currently contains the top 8,777 enterprise SaaS businesses, of which 3,906 are in the United States, 2,335 do not have a location listed but may be in the United States (for example, Hewlett Packard, Xerox, ADP, etc.), and 2,536 are located outside of the United States. Since Enterprise Businesses are a segment of B2B Businesses, there may be more B2B SaaS companies that are not included on this list.
Additionally, Cardin does not disclose the specifics of all 25,000 Enterprise SaaS Businesses it claims to track. Of the 8,777 Enterprise SaaS Businesses it discloses, 364 are public, 6 in the process of IPO registration, 4,575 privately held, and 2,668 do not list a status.
Key global and industry trends appear to be a shift towards artificial intelligence (ex. Blueshift, Finn.ai, and Fiind), and marketing automation and customer acquisition (ex. Sales & Orders, Exponea, Tagoce, Iterable, Sendwithus, SendGrid, and SparkPost).