All three major US stock indexes were up in late-morning trading Friday, as market participants parsed Federal Reserve Chairman Kevin Warsh's speech at the Jackson Hole Economic Policy Symposium in Wyoming.

In the speech, Warsh said inflation is the more concerning part of the Fed's dual mandate while recommitting to the central bank's 2% policy target. The new chair also restated his belief that forward guidance can handcuff the Fed, preventing it from making key decisions.

In company news, Advent and Stripe have abandoned their $50 billion bid to buy PayPal (PYPL), Bloomberg reported Friday, citing people familiar with the matter. PayPal shares were down 11.5% around midday.

Marvell Technology (MRVL) reported fiscal Q2 adjusted earnings late Thursday of $0.94 per diluted share, up from $0.67 a year earlier and above the FactSet consensus estimate of $0.93. Fiscal Q2 revenue was $2.74 billion, up from $2.01 billion a year ago and above the FactSet consensus of $2.72 billion. For fiscal Q3, the company said it expects adjusted EPS of $1.10, plus or minus $0.05, on revenue of $3.15 billion, plus or minus 5%. Analysts polled by FactSet expect $1.08 and $3.04 billion, respectively. Marvell shares were down 8.2%.

Chevron (CVX) is nearing a deal to expand its operations in Venezuela by adding two new heavy-oil fields to its portfolio, The Wall Street Journal reported Friday, citing people familiar with the matter. Halliburton (HAL) is also in discussions to provide its suite of equipment to oil producers in Venezuela, the report said, citing the people. Chevron and Halliburton shares were up 0.6% and 1%, respectively.

BioNTech (BNTX) said Friday that it terminated its phase 2 trial evaluating autogene cevumeran as an adjuvant monotherapy in patients with high-risk stage II or stage III colorectal cancer. The trial's independent safety board recommended discontinuing treatment and ending the trial, as further continuation was unlikely to change the efficacy outcome, the company said. BioNTech shares were down 7.5%.

Amazon.com (AMZN) has signed a power purchase agreement in Germany and invested in four Swedish wind energy projects, the company said Friday. The e-commerce giant said it agreed to buy 600 megawatts of electricity from the planned Gennaker offshore wind farm in the Baltic Sea. Shares of Amazon were up 4.2%.

Price: 54.41, Change: -7.06, Percent Change: -11.49