The most significant insider transaction on today's list comes from a 13D filing by Jeff Ubben’s Value Act.

The hedge fund revealed an ownership stake of 6.70% in The New York Times Company $NYT.

The largest insider buy on today’s list is a Form 4 filing by the executive chairman of Energy Transfer LP $ET, who revealed a purchase worth $12.6 million.

Director Matthew R. Cohler revealed an insider buy worth $991,484 in KKR & Co $KKR.

George L. Ball, the chief financial officer at Parsons Corporation $PSN, filed a Form 4 revealing a purchase of 35,000 shares of PSN.

That’s equivalent to $1,452,500 worth of his company's stock.

Today’s most significant insider transaction report is another Form 4 filing by Warren Buffett’s Berkshire Hathaway $BRK.A.

Buffet continues to increase his position in Occidental Petroleum $OXY, as he just reported an additional purchase, this one worth roughly $390 million.

The largest insider buy on today’s list is a Form 4 filing by the president and CEO of TransUnion $TRU, who revealed a purchase of $1.9 million in the credit reporting agency.

The chief commercial officer of First Solar $FSLR reported a purchase of 9,946 shares, worth roughly $1 million in the solar panel manufacturer.

The most significant insider transaction on today’s list is a Form 4 filing for Pinterest $PINS.

We wrote about PINS on July 15, when Elliott Management announced a large activist stake.

Insiders are finally buying into the summer rally. We haven’t seen this much action on our Hot List in months!

The largest insider transaction on today’s list is a Form 4 filing by the Chairman and CEO of American Assets Trust $AAT, with a roughly $1 million purchase.

B. Riley Financial $RILY Director Randall Paulson reported another purchase of stock in the asset manager. His last purchase was in early May.

The largest insider transaction on today's list is a Form 4 filing by Artal Group, which reported a purchase of roughly $40.4 million in Lexicon Pharmaceuticals $LXRX.

Artal Group now owns 83,835,950 LXRX shares, representing a roughly 47.5% ownership stake.

CD&R Investment Associates disclosed the purchase of approximately $6 million worth of Beacon Roofing Supply $BECN in a Form 4 on Friday.

The firm now owns 24,348,048 shares, which represents a roughly 35% ownership stake in the mid-cap building products company.

Insiders are buying up regional banks this week.

Independent Director Robert Stallings reported an additional  purchase of $1.2 million in Texas Capital Bancshares $TCB, as he continues to build his position.

The president and CEO of Heritage-Crystal Clean $HCCI reported a purchase of 150,000 shares, roughly equivalent to $4,000,000 worth of stock.

The only 13D on our list today was filed by Inclusive Capital Partners LP.