ZBIO Zenas BioPharma, Inc.

NASDAQ
$31.91

Zenas BioPharma, Inc. (ZBIO) 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 0 buyers in the last 30 days 0 buyers in the last 90 days 0 sellers in the last 90 days
Insiders buying
6
25 transactions
Insiders selling
0
0 transactions
Purchases
$29.0M
1,528,648 shares
Sales
$0
0 shares
Net activity
$29.0M
purchases less sales

Where they traded

Buy Sell Dot area is proportional to transaction value.

Last open-market purchase: May 18, 2026 , by MOULDER LEON O JR .

Recent open-market activity

Date Insider Role Action Shares Price Value Held after
MOULDER LEON O JR Chief Executive Officer Buy 60,000 $16.88 $1.0M 96,928
MOULDER LEON O JR Chief Executive Officer Buy 35,000 $17.62 $616.7K 1,786,039
MOULDER LEON O JR Chief Executive Officer Buy 25,000 $18.02 $450.5K 1,751,039
Buy 150,000 $20.00 $3.0M 2,359,025
Lu Hongbo 2 fills Director Buy 78,768 $19.93 $1.6M 426,736
MOULDER LEON O JR Chief Executive Officer Buy 34,000 $19.31 $656.5K 1,726,039
MOULDER LEON O JR Chief Executive Officer Buy 20,000 $18.23 $364.6K 1,692,039
Allen Patricia L Director Buy 4,160 $26.36 $109.7K 19,860
Allen Patricia L 3 fills Director Buy 15,700 $24.85 $390.1K 15,700
Lu Hongbo Director Buy 25,985 $22.50 $584.7K 347,968
MOULDER LEON O JR Chief Executive Officer Buy 57,000 $17.96 $1.0M 423,155
MOULDER LEON O JR Chief Executive Officer Buy 20,000 $16.55 $331.0K 366,155
MOULDER LEON O JR Chief Executive Officer Buy 30,000 $16.30 $489.0K 346,155
MOULDER LEON O JR Chief Executive Officer Buy 50,000 $16.38 $819.0K 316,155
2 fills Buy 126,315 $19.00 $2.4M 1,917,895
ENRIGHT PATRICK G 2 fills Director Buy 117,255 $19.19 $2.3M 1,832,669
Nunn Jason Raleigh Director Buy 63,158 $19.00 $1.2M 1,173,395
Buy 316,219 $19.00 $6.0M 2,209,025
Lu Hongbo Director Buy 263,160 $19.00 $5.0M 321,983
MOULDER LEON O JR See Remarks Buy 36,928 $20.85 $769.9K 36,928

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.