Clearsign Technologies Corp
Other Technology · Tulsa, Oklahoma
Clearsign Technologies Corp is a other technology company based in Tulsa, Oklahoma. It has raised at least $25.3 million across 4 known rounds, of which $22.4 million was reported to the SEC on 4 Form D filings, most recently in 2024.
| Date | Round | Amount | Raised to date | Lead investor | Source |
|---|---|---|---|---|---|
| 2026-07-31 | — | $1.8M | $25.3M | SEC Form D | |
| 2024-07-09 | — | $4.3M | $23.5M | SEC Form D | |
| 2024-05-08 | — | $5.0M | $19.2M | SEC Form D | |
| 2020-10-02 | — | $1.3M | $14.2M | SEC Form D | |
| 2018-07-23 | — | $11.7M | $12.9M | SEC Form D | |
| 2011-03-18 | — | $100K | $1.2M | SEC Form D | |
| 2011-02-03 | — | $1.1M | $1.1M | SEC Form D |
SEC rows are Form D filings, where the amount is what was actually sold and amendments update a round rather than adding one. Press rows are split between company-issued releases or wires and editorial or third-party coverage. The total is therefore a floor: a round nobody reported is a round we cannot see. A buyout or control change appears in the timeline but is never added to the total: that money goes to shareholders, not into the company.
Form D is the notice a company files with the SEC when it sells securities without registering them. It reports the amount sold, not a valuation. Figures here are what the filing says. Where a filing is silent, the field is left blank rather than estimated. “Total raised” adds press-reported rounds that never appear in a filing, so it is a floor rather than an audited sum: press amounts are the figures the company announced, and a round nobody reported is a round we cannot see.