CTSO CytoSorbents Corporation

NASDAQ
$4.38

CytoSorbents Corporation (CTSO) Insider Activity

What the officers, directors and large holders did with their own shares. Only open-market purchases and sales count toward the totals — grants, option exercises and shares withheld for tax are compensation mechanics, not decisions, and they're listed separately below.

30D 90D 6M 1Y
Insider signal Bullish Insiders bought more than they sold over this window — uncommon at any size.
Cluster activity 3 buyers in the last 30 days 3 buyers in the last 90 days 0 sellers in the last 90 days
Insiders buying
4
9 transactions
Insiders selling
0
0 transactions
Purchases
$246.7K
566,042 shares
Sales
$0
0 shares
Net activity
$246.7K
purchases less sales

Where they traded

Buy Sell Dot area is proportional to transaction value.

Last open-market purchase: September 15, 2026 , by Sobel Alan D. .

Recent open-market activity

Date Insider Role Action Shares Price Value Held after
Sobel Alan D. 3 fills Director Buy 2,500 $6.10 $15.3K 9,887
Capponi Vincent 2 fills President and COO Buy 2,073 $6.05 $12.5K 40,387
Chan Phillip P. Chief Executive Officer Buy 200,000 $0.35 $70.0K 1,944,432
MARIANI PETER J Chief Financial Officer Buy 100,000 $0.44 $44.0K 638,113
Chan Phillip P. Chief Executive Officer Buy 10,333 $0.43 $4.4K 1,744,432
Chan Phillip P. Chief Executive Officer Buy 251,136 $0.40 $100.5K 1,734,099

Form 4s are due within two business days of a transaction, so this is close to real time — unlike the quarterly 13F data on the Institutional tab. A single large sale often reflects a prearranged 10b5-1 plan rather than a fresh view, so read a pattern of sales rather than any one of them.