NIERENBERG DAVID

10% owner at NATUS MEDICAL INC · on record since Aug 21, 2006
10% owner at MEXICAN RESTAURANTS INC · on record since Jul 10, 2006
10% owner at PEDIATRIC SERVICES OF AMERICA INC · on record since Jul 10, 2006
10% owner at RADISYS CORP · on record since Oct 31, 2006
10% owner at ELECTRO SCIENTIFIC INDUSTRIES INC · on record since Mar 29, 2007
10% owner at POTBELLY CORP · on record since Aug 7, 2024
10% owner at MEDCATH CORP · on record since Dec 31, 2007
10% owner at MOVE INC · on record since May 30, 2008
10% owner at ASSET ACCEPTANCE CAPITAL CORP · on record since Jun 30, 2008
Not subject to Section 16 at Azenta, Inc. · on record since Jul 25, 2008
10% owner at Azenta, Inc. · on record since Jul 23, 2008
10% owner at AMEDISYS INC · on record since Jun 30, 2003
Director at NATUS MEDICAL INC · on record since Jul 22, 2003
Director at MEXICAN RESTAURANTS INC · on record since Aug 26, 2003
10% owner at VIRAGE INC · on record since Aug 26, 2003
Director at GARDEN FRESH RESTAURANT CORP /DE/ · on record since Aug 27, 2003
10% owner at GARDEN FRESH RESTAURANT CORP /DE/ · on record since Aug 27, 2003
Director at ELECTRO SCIENTIFIC INDUSTRIES INC · on record since May 16, 2011
Former Director at · on record since Jun 17, 2004
Director at · on record since Mar 5, 2004
10% owner at · on record since Mar 5, 2004
Director at · on record since Apr 17, 2015
Director at · on record since May 26, 2016
Director at · on record since Jun 5, 2018
Director at · on record since Mar 17, 2020
10% owner at · on record since Mar 17, 2020
Director at · on record since Apr 6, 2005

Insider trading activity of NIERENBERG DAVID

Transactions on record: 551; since Aug 1, 2003

Open-market buys: 345; $46.2M

Open-market sells: 78; $33M

Companies traded: 18; last filing Mar 31, 2025

Figures computed from official regulatory filings — .

Companies where NIERENBERG DAVID has traded

5 tx · $322K · Mar 31, 2025
120 tx · $9.6M · Dec 15, 2023
6 tx · $799.6K · Jun 21, 2021
69 tx · $29.9M · Oct 16, 2020
20 tx · $637K · Mar 17, 2020
30 tx · $1.5M · Jan 3, 2014
23 tx · $4.9M · Dec 5, 2013
18 tx · $1.5M · Oct 9, 2012
17 tx · $1.1M · Jun 2, 2011
53 tx · $21.2M · Jan 26, 2010
34 tx · $5.7M · Nov 25, 2008
85 tx · $10.5M · Jul 5, 2006
16 tx · $359.7K · Dec 29, 2005
27 tx · $1.5M · Sep 7, 2005

Track record of NIERENBERG DAVID

Statistical track record

Free account

Open-market buys: 363

Last buy: Mar 28, 2025

Win rates, median returns and the proven-insider analysis come with a free account.

Transaction history of NIERENBERG DAVID

Co-insiders of NIERENBERG DAVID

This page republishes public regulatory disclosures.

Company	Filed	Type	Qty	Price	Value · USD	Signals	Src
POTBELLY CORPListing unverified	Mar 31, 2025	Buy	22,169	9.36 USD	$207.5K	conv 31	SEC
POTBELLY CORPListing unverified	Jan 10, 2025	Buy	7,500	9.23 USD	$69.2K	conv 23	SEC
POTBELLY CORPListing unverified	Jan 10, 2025	Buy	100	9.24 USD	$924	conv 20	SEC
POTBELLY CORPListing unverified	Dec 20, 2024	Buy	3,150	9.34 USD	$29.4K	conv 32First in 12mo	SEC
POTBELLY CORPListing unverified	Dec 20, 2024	Buy	1,590	9.40 USD	$14.9K	conv 32First in 12mo	SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Dec 15, 2023	Buy	11,948	3.72 USD	$44.4K	conv 43Cluster	SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Dec 15, 2023	Buy	748	3.72 USD	$2.8K	conv 43Cluster	SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Dec 15, 2023	Buy	6,785	3.72 USD	$25.2K	conv 43Cluster	SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Dec 13, 2023	Buy	3,752	3.19 USD	$12K	conv 54ClusterFirst in 12mo	SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Dec 13, 2023	Buy	20,310	3.53 USD	$71.7K	conv 43Cluster	SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Dec 13, 2023	Buy	4,954	3.42 USD	$16.9K	conv 43Cluster	SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Dec 13, 2023	Buy	858	3.42 USD	$2.9K	conv 43Cluster	SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Dec 13, 2023	Buy	1,272	3.53 USD	$4.5K	conv 43Cluster	SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Dec 13, 2023	Buy	5,254	3.19 USD	$16.8K	conv 52ClusterFirst in 12mo	SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Dec 13, 2023	Buy	6,923	3.42 USD	$23.7K	conv 43Cluster	SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Dec 13, 2023	Buy	11,536	3.53 USD	$40.7K	conv 43Cluster	SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Jul 5, 2023	Award	241,096	0.00 USD	n/a (Non-cash transaction: the filing states a price of zero (award, gift, exercise))		SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Jun 9, 2023	Sell	-211,080	0.63 USD	$133K		SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Jun 9, 2023	Sell	-538,920	0.63 USD	$339.5K		SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Jan 24, 2023	Award	13,179	0.00 USD	n/a (Non-cash transaction: the filing states a price of zero (award, gift, exercise))		SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Aug 8, 2022	Award	165,289	0.00 USD	n/a (Non-cash transaction: the filing states a price of zero (award, gift, exercise))		SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Mar 23, 2022	Other	1,036,214	0.00 USD	n/a (Non-cash transaction: the filing states a price of zero (award, gift, exercise))		SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Mar 23, 2022	OtherD (derivative)	0	—	n/a (No price was disclosed in the filing)		SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Mar 23, 2022	Other	1,680,008	0.00 USD	n/a (Non-cash transaction: the filing states a price of zero (award, gift, exercise))		SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Mar 23, 2022	OtherD (derivative)	0	—	n/a (No price was disclosed in the filing)		SEC

Company	Filed	Type	Qty	Price	Value · USD	Signals	Src
POTBELLY CORPListing unverified	Mar 31, 2025	Buy	22,169	9.36 USD	$207.5K	conv 31	SEC
POTBELLY CORPListing unverified	Jan 10, 2025	Buy	7,500	9.23 USD	$69.2K	conv 23	SEC
POTBELLY CORPListing unverified	Jan 10, 2025	Buy	100	9.24 USD	$924	conv 20	SEC
POTBELLY CORPListing unverified	Dec 20, 2024	Buy	3,150	9.34 USD	$29.4K	conv 32First in 12mo	SEC
POTBELLY CORPListing unverified	Dec 20, 2024	Buy	1,590	9.40 USD	$14.9K	conv 32First in 12mo	SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Dec 15, 2023	Buy	11,948	3.72 USD	$44.4K	conv 43Cluster	SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Dec 15, 2023	Buy	748	3.72 USD	$2.8K	conv 43Cluster	SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Dec 15, 2023	Buy	6,785	3.72 USD	$25.2K	conv 43Cluster	SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Dec 13, 2023	Buy	3,752	3.19 USD	$12K	conv 54ClusterFirst in 12mo	SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Dec 13, 2023	Buy	20,310	3.53 USD	$71.7K	conv 43Cluster	SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Dec 13, 2023	Buy	4,954	3.42 USD	$16.9K	conv 43Cluster	SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Dec 13, 2023	Buy	858	3.42 USD	$2.9K	conv 43Cluster	SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Dec 13, 2023	Buy	1,272	3.53 USD	$4.5K	conv 43Cluster	SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Dec 13, 2023	Buy	5,254	3.19 USD	$16.8K	conv 52ClusterFirst in 12mo	SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Dec 13, 2023	Buy	6,923	3.42 USD	$23.7K	conv 43Cluster	SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Dec 13, 2023	Buy	11,536	3.53 USD	$40.7K	conv 43Cluster	SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Jul 5, 2023	Award	241,096	0.00 USD	n/a (Non-cash transaction: the filing states a price of zero (award, gift, exercise))		SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Jun 9, 2023	Sell	-211,080	0.63 USD	$133K		SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Jun 9, 2023	Sell	-538,920	0.63 USD	$339.5K		SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Jan 24, 2023	Award	13,179	0.00 USD	n/a (Non-cash transaction: the filing states a price of zero (award, gift, exercise))		SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Aug 8, 2022	Award	165,289	0.00 USD	n/a (Non-cash transaction: the filing states a price of zero (award, gift, exercise))		SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Mar 23, 2022	Other	1,036,214	0.00 USD	n/a (Non-cash transaction: the filing states a price of zero (award, gift, exercise))		SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Mar 23, 2022	OtherD (derivative)	0	—	n/a (No price was disclosed in the filing)		SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Mar 23, 2022	Other	1,680,008	0.00 USD	n/a (Non-cash transaction: the filing states a price of zero (award, gift, exercise))		SEC
FLOTEK INDUSTRIES INC/CN/Listing on record	Mar 23, 2022	OtherD (derivative)	0	—	n/a (No price was disclosed in the filing)		SEC