In-Depth Analysis of Large-Scale Share Purchases by Zenas BioPharma (ZBIO)'s CEO

Based on the comprehensive data I have collected, I now present this professional analysis report.

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According to SEC Form 4 filings, Lonnie Moulder, Founder and CEO of Zenas BioPharma, spent

(100,000 shares at $16.39 per share) to purchase the company’s stock on [0]. After the purchase, Mr. Moulder directly and indirectly holds a total of of the company [0].

Purchase Date	Purchase Amount	Purchase Price	vs. Current Share Price ($16.08)
2024-12-03	$718,100	$10.26	+56.8%
2025-02-18	$166,750	$6.67	+141.1%
2025-10-07	$769,949	$20.85	-22.9%
2026-01-07	$1,639,000	$16.39	-1.9%

Notably, on October 9, 2025, multiple directors and major shareholders also conducted large-scale share purchases totaling

, demonstrating high alignment in the management and board’s confidence in the company’s prospects [0].

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Indicator	Value	Interpretation
Market Capitalization	$674 million	Mid-sized biopharmaceutical company
Current Ratio	5.23	Sound financial condition
Cash and Cash Equivalents	$302 million	Sufficient operating capital
ROE	-59.19%	In R&D investment phase, in line with expectations
Debt Risk	Low	Controllable liability level

The company is currently in the clinical R&D phase and has not yet generated product revenue; its loss-making status is normal for the biopharmaceutical industry. The

, combined with the expected milestone payment of $75 million from Royalty Pharma, is expected to support operations until [0].

Time Period	Change	Background
5 Days	-55.71%	Plunge after Phase 3 data release
1 Month	-57.87%	Market digesting negative sentiment
6 Months	+53.29%	Driven by expectations of trial success
1 Year	+98.03%	Long-term growth trend remains unchanged

On January 5, 2026, the company announced positive results from its Phase 3 INDIGO trial — Obexelimab demonstrated a

in IgG4-related disease, meeting the primary and all secondary endpoints [0]. However, the stock price plummeted on the same day for the following reasons:

1. Underperforming compared to competitors
   : Amgen’s Uplizna (already FDA-approved) showed superior efficacy in the same indication
2. Excessively high market expectations
   : The stock price had nearly doubled over the previous year due to expectations of trial success
3. Analysts downgraded ratings
   : Morgan Stanley downgraded its rating from “Overweight” to “Equal Weight” on January 6, 2026 [0]
4. Legal risks
   : Multiple law firms announced the initiation of shareholder investigations into the company [0]

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The CEO’s large-scale share purchase immediately following the stock price plunge conveys the following messages:

• Remaining confident in the commercialization prospects of Obexelimab
• Believing the current stock price is undervalued
• Willing to “endorse” the company’s value with personal funds

The timing of Moulder’s purchase (when the stock price fell from a high of $20.85 to $16.39) indicates that he adopted a

rather than chasing highs. This is fundamentally different from pure “stock price support” actions aimed solely at stabilizing the stock price.

The CEO has made continuous share purchases (4 times) over the past year, totaling $3.29 million, demonstrating his recognition of the company’s long-term value [0].

Executives of biopharmaceutical companies typically conduct stock sales or purchases related to tax planning at the end of the year. The January 2026 share purchase may be related to 2025 tax planning.

Moulder holds a large number of stock options (1.46 million options granted at IPO with an exercise price of $17.00), and the share purchase may be related to option vesting and exercise decisions [0].

Although insiders usually have more information, the CEO’s share purchase

that the company has no undisclosed material risks.

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According to academic research, insider buying signals have the following characteristics [1][2]:

Research Finding	Specific Data
Excess Returns from Purchases	Stocks purchased by insiders outperform the market by an average of 4.8% annually
Sales Have No Predictive Power	Insider stock sales have no significant predictive effect on future stock prices
Pharmaceutical Industry Characteristics	Insider transactions in biopharmaceuticals are highly correlated with clinical trial progress

Insider transactions in biopharmaceutical companies have unique patterns:

1. Event-driven transactions
   : Insider trading activity increases significantly before and after the release of clinical trial results [2]
2. Liquidity needs
   : Executives of companies in the R&D phase may regularly sell stocks due to their compensation structure
3. “Lottery effect”
   : When the prospect of clinical success attracts attention, insiders may cash in on market optimism

: Insider purchases in the biopharmaceutical field should be comprehensively judged in combination with clinical trial progress, competitive landscape, and regulatory prospects, rather than simply being regarded as a “buy signal” [2].

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• Successful Phase 3 trial of Obexelimab, meeting primary and all secondary endpoints
• Approximately 20,000 IgG4-RD patients in the U.S., with clear unmet medical needs
• The company has sufficient cash, no concerns about operating capital
• Analyst consensus remains “Buy”, with a target price of $44.00 implying 173.6% upside potential
• Continuous insider purchases demonstrate management confidence

• Obexelimab’s competitiveness is questionable compared to Amgen’s Uplizna
• Uncertainty about FDA approval timeline and commercialization prospects
• Legal litigation risks may affect the company’s reputation and resource allocation
• Inherent risk of clinical trial failure in the biopharmaceutical industry

Evaluation Dimension	High-Confidence Signal	Low-Confidence Signal
Purchase Scale	Large-scale purchase (> $1 million)	Small-scale purchase (< $100,000)
Purchase Frequency	Sustained, multiple purchases	One-time purchase
Purchase Timing	Buying after stock price decline	Chasing highs after stock price rise
Purchaser Identity	CEO/Founder share purchase	Small-scale purchase by independent director
Supporting Actions	Concurrent share purchases by management	Purchase by only a single executive

: The CEO’s share purchase is a , meeting multiple high-confidence criteria (large-scale, sustained, buy-the-dip, concurrent purchases by multiple executives).

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1. The CEO’s share purchase does reflect management confidence, but it needs to be interpreted in context

Moulder’s $1.63 million share purchase occurred after the company’s stock price plummeted 51% due to underwhelming Phase 3 trial results. This purchase likely reflects the CEO’s view that the market overreacted, and the current stock price does not fully reflect the potential value of Obexelimab as a first-line therapy.

2. Fundamentals have indeed shown positive changes, but the market has not yet recognized them

The successful Phase 3 trial of Obexelimab (56% reduction in flare risk) is a clear positive development. However, due to competitive pressure from Amgen’s Uplizna, the market is cautious about its commercialization prospects.

3. Insider buying is an auxiliary indicator, not a decisive factor

Academic research shows that insider buying generates an average excess return of 4.8%, but this is only a statistical pattern; specific cases require comprehensive judgment based on the company’s fundamentals, industry prospects, and valuation level.

Investor Type	Recommendation
Risk-Seeking Investors	May consider establishing a small position, setting a stop-loss at $14.00 and a target price at $25.00
Value Investors	Wait for the stock price to stabilize (usually 4-8 weeks), then make a decision based on BLA submission progress
Wait-and-See Investors	Reassess after paying attention to the 24-week MoonStone data in Q1 2026, SLE trial progress, and Uplizna’s market performance

• Biopharmaceutical investments are highly uncertain; clinical trial failure may lead to significant losses
• Legal litigation may affect the company’s operations and resource allocation
• Changes in the competitive landscape may alter commercialization prospects
• Stock price fluctuations may exceed expectations

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[0] Jinling API Data - Zenas BioPharma company profile, financial analysis, SEC filings, and insider transaction records

[1] Investopedia - “Insider Buying or Selling Indicators” (https://www.investopedia.com/insider-buying-or-insider-selling-indicators-11760828)

[2] AInvest - “Insider Selling in Biotech: A Signal or a Fluke?” (https://www.ainvest.com/news/insider-selling-biotech-signal-fluke-2601)

[3] MarketChameleon - “Zenas BioPharma Faces Legal Scrutiny” (https://marketchameleon.com/Blogpost/2026/01/07/zenas-biopharma-faces-legal-scrutiny-mixed-indigo-trial-results-drug-viability)

[4] Seeking Alpha - “Zenas Maintains Strong Buy” (https://seekingalpha.com/article/4857350-zenas-maintaining-strong-buy-as-cross-trial-comparison-of-obexelimab-should-not-be-factor)

[5] SEC Form 4 Filing Records - secform4.com (https://www.secform4.com/insider-trading/1953926.htm)