Here is a detailed review of the largest insider purchases and sales filed for May 11 through May 13, 2026, focusing on transactions that stood out by dollar value, volume or potential signal. The entries below reproduce reported quantities, price ranges and any valuation context disclosed alongside each filing.
Top buys
RA Capital Management and affiliated funds - Artiva Biotherapeutics
RA Capital Management, L.P. and its related entities completed a sizable equity investment in Artiva Biotherapeutics, Inc. By filings dated May 11, 2026, the investors purchased 6,510,416 shares of Artiva common stock for approximately $75 million at a per-share price of $11.52. In an associated transaction, RA Capital Healthcare Fund, L.P. bought 2,170,138 pre-funded warrants priced at $11.5199 each, with a nominal exercise price of $0.0001.
The notes on the warrants indicate they are immediately exercisable and do not carry an expiration date. However, exercise is limited by beneficial ownership rules that prevent the fund from owning more than 9.99% of Artiva’s total outstanding common stock. The purchase arrives as Artiva has experienced a sharp run-up in equity value - the company’s stock is reported to have climbed over 412% in the past year - though shares have retreated roughly 15% in the most recent week to trade around $10.50.
InvestingPro analysis appended to the disclosure highlights that Artiva holds more cash than debt and reports a robust current ratio of 8.16, indicating short-term liquid assets substantially exceed short-term liabilities. The analysis also notes the company recorded an EBITDA loss of $89.4 million over the trailing twelve months and remains unprofitable.
William H. Gates III and Cascade Investment - Republic Services
William H. Gates III and Cascade Investment, L.L.C. purchased a combined total of 509,150 shares of Republic Services, Inc. across transactions executed between May 11 and May 13, 2026. The aggregate cost of these purchases was approximately $100.5 million, with per-share prices ranging from $197.18 to $203.6701.
On May 11, filings show an acquisition of 78,150 shares at a weighted-average price of $197.18, with individual trade prices between $196.83 and $197.65. The trades occurred while Republic Services shares were trading near a 52-week low of $196.41. InvestingPro commentary included with the filing indicates the stock is trading above its Fair Value estimate.
Brian N. Sheth and Haveli-related entities - Blend Labs
Director Brian N. Sheth and investment vehicles associated with him, including Haveli Brooks Aggregator, L.P., purchased a combined 1,951,635 shares of Blend Labs, Inc. Class A common stock in transactions from May 11 through May 13, 2026. The purchases totaled about $2.79 million, with per-share prices ranging from $1.3371 to $1.465.
The acquisitions occurred as Blend’s stock traded near a 52-week low of $1.31 and after a near-term decline of close to 10% over the previous week. The InvestingPro assessment cited in the filing indicates the shares appear undervalued at current levels, with a Fair Value estimate of $1.48.
ADAR1 Capital Management and Daniel Schneeberger - Rallybio
ADAR1 Capital Management, LLC, a ten-percent holder in Rallybio Corp, together with its sole manager Daniel Schneeberger, bought 50,800 shares of Rallybio common stock for a total of $711,054. Transactions were reported on May 11 and May 12, 2026, with executed prices between $13.8288 and $14.00 per share.
The filings detail that on May 11 ADAR1 purchased 5,100 shares at a weighted average price of $13.9984, with transaction prices ranging from $13.9164 to $14.0000. Subsequent purchases included blocks of 25,000 and 19,900 shares at $14.0000 per share. Rallybio shares were trading close to a 52-week high of $15.31 and had gained roughly 480% over the past year; InvestingPro notes, however, that the stock appears overvalued relative to its Fair Value estimate, trading at $14.35 at the time of reporting.
Andrew M. Schleimer, CFO - TKO Group Holdings
Andrew M. Schleimer, the chief financial officer of TKO Group Holdings, Inc., reported purchases of the company’s Class A common stock totaling about $499,953 on May 13, 2026. The transactions consisted of two separate buys adding up to 2,696 shares, executed between $184.99 and $186.21 per share.
Mr. Schleimer’s initial purchase on the day was 1,696 shares at a weighted average price of $184.99, with recorded prices ranging from $184.44 to $185.20. He later acquired an additional 1,000 shares at a weighted average price of $186.21, with prices between $185.60 and $186.35. After these trades, his direct holdings in TKO Group Holdings Class A common stock total 30,240 shares. At the time of the filing, the stock was quoted at $183.61, and InvestingPro’s evaluation suggested the company’s shares appeared undervalued relative to Fair Value.
Top sells
Ashok Mishra, EVP and COO - Innodata
Ashok Mishra, executive vice president and chief operating officer of Innodata Inc., sold 242,901 shares of the company’s common stock on May 12, 2026, for proceeds of approximately $21.9 million. The disposition occurred in two blocks: 234,000 shares at a weighted average price of $90.02, with individual trade prices ranging from $90.00 to $90.90; and 8,901 shares at a weighted average price of $93.56, with prices between $93.14 and $94.00.
The filings indicate these sales followed the exercise of stock options for an equivalent number of shares, and the reporting person disclosed the proceeds were earmarked for personal investment and financial planning objectives, such as retirement planning and diversification. The timing comes as Innodata’s shares have risen 158% over the prior year and are trading well above InvestingPro’s Fair Value estimate.
Spencer Collins, Chief Legal Officer - ARM Holdings
Spencer Collins, ARM Holdings PLC’s chief legal officer, reported sales totaling $11,001,747 on May 11, 2026. The transactions involved 51,961 ordinary shares sold in the form of American Depositary Shares, each representing one ordinary share. Weighted average sale prices ranged from $207.77 to $214.41 per share.
ARM shares closed at $212.65 on the day of the transaction and were trading at $221.37 subsequently, reflecting a strong year-to-date gain of 90% and a 64% return over the past year, according to the filing.
Anthony J. Wood, CEO and Chairman - Roku
Anthony J. Wood, Roku’s CEO and chairman, sold 75,000 shares of Class A common stock on May 11, 2026, for total proceeds of $9,659,240. The sales were executed through the Wood 2017 Revocable Trust at prices ranging from $127.61 to $131.22 per share and formed part of a pre-arranged Rule 10b5-1 trading plan.
Prior to these sales, the trust converted 75,000 shares of Class B common stock into an equal number of Class A shares; the filing notes each Class B share can be converted into one Class A share at the option of the reporting person with no expiration date. Roku shares were near a 52-week high of $131.39, having returned 76% over the last year, and InvestingPro’s analysis cited with the filing suggested Roku was trading below Fair Value with a PEG ratio of 0.33.
Rodrigo Cardoso Barbosa, President and CEO - Aura Minerals
Rodrigo Cardoso Barbosa sold a total of 115,000 common shares of Aura Minerals Inc. over May 11 and May 12, 2026, generating approximately $9,430,450 in proceeds. On May 11 he sold 60,000 shares at a weighted average price of $81.43, and on May 12 an additional 55,000 shares at a weighted average price of $82.63. The transactions had individual trade prices ranging from roughly $79.52 to $84.96. Following these sales, Mr. Barbosa’s direct holdings stand at 739,745 common shares.
Third Rock Ventures V, L.P. - Rapport Therapeutics
Third Rock Ventures V, L.P., a significant shareholder in Rapport Therapeutics, Inc., disposed of 133,618 shares of common stock on May 11, 2026, for total proceeds of $5,377,322. The weighted average sales price was $40.244, with individual trades between $40.00 and $40.665. The selling party reported the transactions were executed pursuant to a Rule 10b5-1 trading plan adopted on November 21, 2025. RAPP shares were trading near a 52-week high of $42.27 after a 281% gain over the past year.
Observations and context included in filings
The filings attest to a mix of motivations and methods behind the trades. Several purchases appear to be concentrated investments by institutional or affiliated funds and company insiders, occasionally accompanied by beneficial ownership limitations for warrant exercises. Large sales included both planned dispositions under Rule 10b5-1 plans and option-exercise related sales tied to personal financial planning.
Where third-party valuation commentary is provided, InvestingPro assessments were cited in the disclosures. Those assessments described selected names as overvalued, undervalued or trading above Fair Value relative to their published estimates, and also highlighted balance-sheet features such as cash-versus-debt positions and current ratios in the case of Artiva.
Bottom line for market observers
Insider transactions can offer a window into how executives and major shareholders are managing exposure to their firms. Purchases by prominent investors and directors can be interpreted as signals of confidence, while sales may reflect pre-planned liquidity management, diversification, or personal financial planning. This collection of filings from mid-May 2026 shows both concentrated buying activity - including a major equity purchase by William H. Gates III and Cascade Investment at Republic Services - and sizable monetizations at multiple companies through planned strategies and option exercises.
Investors should treat these disclosures as one input among many when forming investment decisions. The filings contain concrete transaction terms and, where included, third-party valuation notes; they do not provide definitive causation for future performance.