11981-01Applied Biosystems — ABI founded 1981 (Foster City, CA). First commercial instrument: Model 470A Protein Sequencer (1982); first commercial DNA sequencer, the Model 370A, in 1987. Now a Thermo Fisher brand via Life Technologies.
21998-04Illumina founded — Illumina incorporated 1 April 1998 in San Diego; it entered sequencing by acquiring Solexa (completed January 2007), whose sequencing-by-synthesis chemistry became the industry workhorse.
32000-01454 founded — 454 Life Sciences founded 2000 by Jonathan Rothberg; its GS20 (2005) was the first commercial next-generation sequencer. Acquired by Roche in 2007 and phased out by ~2016.
42004-01PacBio founded — Pacific Biosciences founded 2004 (originally Nanofluidics); its first single-molecule real-time (SMRT) instrument, the PacBio RS, shipped in 2011.
52005-01ONT & Complete Genomics — Oxford Nanopore (as Oxford Nanolabs) and Complete Genomics were both founded in 2005. Complete Genomics' DNB human-genome service launched commercially in 2010; it was acquired by BGI in 2013, seeding today's MGI.
62022-01Second wave — A new generation of short-read challengers reached the market — Element Biosciences (AVITI), Ultima Genomics, and Singular Genomics — alongside MGI/BGI's global expansion, lifting the count again after the mid-2010s consolidation.
Approximate count of distinct commercial sequencing-platform makers active over time — an illustrative boom-bust-boom arc, not an exact census. The count climbs through the NGS gold rush (Applied Biosystems Sanger era; Illumina/Solexa; 454; PacBio; Complete Genomics), falls as players are acquired or shut (454 → Roche 2007, line phased out by ~2016; Complete Genomics → BGI 2013; Solexa folded into Illumina 2007), then rises again with a second wave (MGI/BGI outside China, plus Element Biosciences, Ultima and Singular Genomics). Corrections applied during research: ABI's first commercial DNA sequencer (Model 370A) was 1987 — its first commercial instrument was the 470A Protein Sequencer (1982); Complete Genomics' commercial launch was 2010 (2009 was proof-of-concept). Counts are illustrative, so the curve is not forecast.