Check out the companies making headlines before the bell:

Aerojet Rocketdyne (AJRD) – Aerojet Rocketdyne agreed to be bought by rival defense contractor L3Harris Technologies (LHX) for $4.7 billion, or $58 per share in cash. Aerojet Rocketdyne rose 2% in the premarket, while L3Harris fell 1.7%.

Tesla (TSLA) – Tesla shares jumped 3.4% in the premarket after CEO Elon Musk ran a Twitter poll on whether he should remain as Twitter’s chief executive, and that he would abide by the results. Some major Tesla shareholders have expressed concern over Musk trying to run both companies, saying Twitter is a major distraction.

Mesa Air Group (MESA) – Mesa shares surged 6.8% in premarket trading following the airline’s announcement that it is finalizing a deal to run regional flights for United Airlines (UAL) and that it is ending its partnership with American Airlines (AAL).

Sinclair Broadcast Group (SBGI) – Sinclair fell 4.4% in premarket trading after the New York Post reported that bankruptcy is likely for Sinclair’s Diamond Sports Group, which operates 21 regional sports networks.

Meta Platforms (META) – The European Commission said it told Meta that the Facebook parent was abusing its dominant position in online classified ads and that it might be violating EU antitrust laws. The EU also said that Meta could be subject to a fine of up to 10% of annual revenue if it determines that those laws were violated. Meta fell 1.4% in premarket action.

TuSimple (TSP) – TuSimple may announce this week that it is cutting its staff in half, according to people familiar with the matter who spoke to the Wall Street Journal. The self-driving truck startup had about 1,430 employees as of June.

Warner Music Group (WMG) – Warner Music shares rallied 3% in the premarket after Atlantic Equities upgraded the stock to overweight from neutral. The firm said Warner Music has shown that it can continue to deliver growth in streaming despite a difficult economic backdrop.

Moderna (MRNA) – The vaccine maker jumped 3.8% in premarket trading after Jefferies upgraded the stock to buy from hold, noting a robust pipeline beyond Covid treatments.