Nephros

NEPH on Nasdaq. Market value $39m.

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Why it could be worth it

Nothing stands out yet.

Read the warning sign in its own filings

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Who owns it

None of the long-term investors we follow own it. 33 funds in all.

Jun '25
Dec '25
Jun '26
Largest holders overall

From 13F filings for the quarter ended 30 June 2026.

Big holders and activists

3 investors own more than 5%.

  • CD Holding Company, LLC
    Passive investor
    5.7%
    Since 14 September 2026
  • at least 5.6%
    (filed with 2 related holders)
    Since 4 August 2025
  • Wexford Capital LP
    Passive investor
    at least 2.1%−3.6 pts
    (filed with 3 related holders)
    Since 14 September 2026
    What they said

    Item 4 of the Statement is hereby amended to add the following: On September 14, 2026, Wexford Capital effected (i) an in-kind distribution of certain shares of common stock from Wexford Partners 11, L.P. ("WP11"), Wexford 11 Advisors LLC ("WP Advisors") and WPIC 2 LLC ("WPIC2",…

    Read the filing

From Schedule 13D and 13G filings: anyone owning more than 5% must file one.

What insiders did

No insider bought or sold on the open market in the last 12 months.

From Form 4 filings: insiders must report trades in their own company's shares within two days.

Warning signs in its filings

Problems the company itself reported to the SEC, in its own words.

1 serious warning sign in Nephros’ filings.

We look for five warning signs: doubt it can keep going, weak checks on its own accounts, a notice that its past accounts can't be relied on, a change of auditor, and one customer bringing in a big share of sales. We don't check lawsuits, investigations or debt yet.

We checked the auditor's report, internal controls, restatement notices, auditor changes and big customers in the 10-K filed 12 Mar 2026, plus the 10-Q filed 10 Aug 2026 and 4 later 8-Ks.

  • Weak checks on its own accounts

    Serious

    The company said its checks on its own accounts did not work at the end of its latest quarter. Mistakes could slip into the numbers.

    “Based upon this evaluation, the Chief Executive Officer and Chief Financial Officer have concluded that the disclosure controls and procedures were not effective as of June 30, 2026, due to the existence of a material weakness in our internal control over financial reporting, as discussed below.”
    Show the full paragraph
    As required by Rules 13a-15 and 15d-15 under the Exchange Act, the Chief Executive Officer and Chief Financial Officer carried out an evaluation of the effectiveness of the design and operation of the disclosure controls and procedures as of June 30, 2026. Based upon this evaluation, the Chief Executive Officer and Chief Financial Officer have concluded that the disclosure controls and procedures were not effective as of June 30, 2026, due to the existence of a material weakness in our internal control over financial reporting, as discussed below. Notwithstanding such material weakness, management believes that the financial statements included in this Quarterly Report on Form 10-Q present fairly in all material respects the financial position, results of operations and cash flows for the period presented.

    From the 10-Q filed 10 August 2026, Part I, Item 4. Controls and Procedures. Read it in the filing

A 10-K is the yearly report every US company files with the SEC. An 8-K is a short notice of a big event.

The deep dive

Everything above is arithmetic on public filings. The deep dive reads the last ten years of annual reports, the proxy statements, and the earnings calls, then argues the case the way Buffett, Klarman, and Hohn would, and checks every claim against the source.

  • What the business is worth, as a range, and the margin of safety at today’s price
  • Prices to start buying, buy, and buy hard
  • The three things that would make this a mistake
  • Every number footnoted to the filing it came from
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What a finished deep dive looks like

Not advice. Numbers on this page come from SEC filings and are updated each night; prices are updated again after the US market closes. The five-year figures are rounded.