The most significant transaction on today's list comes in a Form 4 from Diversified Healthcare Trust director Adam Portnoy.

Portnoy revealed a purchase of $14.7 million in DHC.

The most significant transaction on today's list comes in a Form 4 filing by Thomas W. Warsop III, president and chief executive officer of ACI Worldwide Inc $ACIW.

Warsop revealed the acquisition of 43,000 shares of ACIW, equivalent to $1 million.

The largest insider buy on today's list comes in a Form 4 filing by the executive vice president and chief people officer of Stericycle $SRCL.

That purchase was worth $308,618.

The largest insider buy on today's list comes in a Form 4 filing by Diversified Healthcare Trust $DHC director Adam Portnoy.

Portnoy reported a purchase of $9.8 million in the small-cap health care REIT.

The largest insider buy on today's list comes in a Form 4 filing by Artal Group SA.

The firm reported a purchase of 27,775,050 shares, equivalent to $72.2 million in Lexicon Pharmaceuticals, Inc. $LXRX.

The largest insider buy on today's list comes in a Form 4 filing by Ben Tisch, senior vice president of corporate development and strategy at Loews Corporation $L.

Tisch reported a purchase of 330,000 shares, equivalent to $18,781,400.

The largest insider buy on today's list comes in a Form 4 filing by Grocery Outlet Holding Corp $GO director Erik D. Ragatz.

Ragatz revealed the purchase of 70,000 shares of GO.

The largest insider buy on today's list comes in a Form 4 filing by CNX Resources Corporation $CNX director Bernard Lanigan Jr.

Lanigan revealed a purchase of 137,835 shares of CNX.

The largest insider buy on today's list comes in a Form 4 filing by Warren Buffett’s Berkshire Hathaway $BRK.A.

In his third filing since May 17, Buffett reported the acquisition of another 4,660,809 shares, equivalent to $272 million.

The largest insider buy on today's list comes in a Form 4 filing by Carl Icahn, who revealed a purchase of $11.2 million in Southwest Gas Holdings $SWX.

Icahn now owns 15.65% of outstanding shares of SWX.

The largest insider buy on today's list comes in a Form 4 filing by the executive chairman of Energy Transfer LP $ET, Kelcy Warren.

Warren revealed yet another ET purchase, this one worth  $4.4 million.

The largest insider buy on today's list comes in a Form 4 filing by Baker Bros Advisors LLC.

The hedge fund revealed a purchase of ACADIA Pharmaceuticals Inc $ACAD worth $22 million, increasing its ownership stake to 26.6%.