Castagna Michael purchased ~$683K in MannKind Corporation stock
MannKind Corporation (MNKD) · Chief Executive Officer · Data via SEC EDGAR Form 4
Price Performance · 10 days before → 90 days after trade
▲ = insider buy date
90-day return
+59.5%vs SPY -5.1%
Trade Details · Public SEC Filing
Insider
Castagna Michael
Role
Chief Executive Officer
Transaction
Open-Market Purchase
Approx. Value
~$683K
Trade Date
Feb 28, 2022
Company
MannKind Corporation
Ticker
MNKDSource
SEC EDGAR Form 4
Why This Trade Stands Out
Very Strong conviction signal
Scored in the top tier across multiple factors. Fewer than 5% of insider trades receive this rating.
~$683K purchase
A significant position. Insiders who invest $500K+ of their own money typically have strong views on their company's near-term outlook.
Chief Executive Officer
CEOs have the deepest knowledge of company operations. Academic research shows CEO purchases outperform other insider trades by a wide margin.
6 insiders traded in the same window
When multiple insiders independently buy within 30 days, it's called a cluster. Studies show clustered insider purchases outperform solo trades significantly, because several people with inside knowledge are reaching the same conclusion.
+59.5% in 90 days (S&P 500: -5.1%)
This trade beat the S&P 500 by 64.7 percentage points over 90 days. We track performance on every insider trade so you can see who consistently outperforms.
How good is Castagna Michael at picking stocks?
Full track record: win rate, average return, and performance vs S&P 500
Castagna Michael wasn't the only one buying.
6 insiders at MannKind Corporation traded within the same 30-day window.
See who else bought · FreeOn February 28, 2022, Castagna Michael — Chief Executive Officer of MannKind Corporation — filed a Form 4 with the SEC disclosing an open-market purchase of approximately ~$683K in MannKind Corporation (MNKD) stock.
This transaction was part of a cluster — 6 insiders at MannKind Corporation made open-market purchases within the same 30-day window. Cluster activity from multiple independent insiders is one of the most studied patterns in insider trading research.
Under Section 16(a) of the Securities Exchange Act of 1934, corporate insiders must report all open-market stock transactions to the SEC within two business days. These filings — known as Form 4s — are publicly available on the SEC's EDGAR database. VeritySignals filters and scores the full Form 4 stream to surface high-conviction signals like this one.
In the 90 days following this trade, MNKD returned +59.5% versus -5.1% for the S&P 500 over the same period.
VeritySignals Conviction Analysis
Full Conviction Analysis
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All data sourced from publicly available SEC Form 4 filings via EDGAR · Not financial advice · Past performance does not guarantee future results.
At a Glance
More MNKD Insider Activity
Castagna Michael
Mar 10, 2026
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Castagna Michael
Mar 10, 2026
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Castagna Michael
Mar 10, 2026
~$259K
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Castagna Michael
Jul 31, 2022
~$40K
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How to Read Insider Trades
What is this?
When company executives buy or sell their own stock, they must report it to the SEC within 2 days. These public filings reveal what the people who know the company best are doing with their own money.
Why does it matter?
Insiders can sell for many reasons (taxes, diversification, expenses), but they generally only buy for one: they think the stock is going up. That's why insider purchases are more predictive than sales.
What makes a trade "strong"?
We score trades on 15+ factors: the insider's role (CEO > director), trade size relative to their salary, whether other insiders also bought (clusters), and historical accuracy of the insider.
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