U.S. stock index futures on Friday were slightly higher, with the spotlight on quarterly results from major banks including bellwether JPMorgan 

JPM

 and lending giant Citigroup 

C

. Wall Street's major averages have posted gains the last two days on favorable consumer and producer inflation data, which has led to market participants upping their bets that the Federal Reserve would have to end its rate-hiking campaign sooner rather than later. Here are some stocks to watch on Friday:

Shares of JPMorgan 

JPM

 gained more than 2% in pre-market trading, after the top U.S. bank comfortably beat Q2 estimates on both top and bottom line. 

The performance of JPM's consumer & community banking and commercial banking units was particularly strong. 

Moreover, the bank increased its guidance for full year net interest income.

Citigroup 

C

 stock also advanced ahead of the opening bell, despite the lender just missing out on Q2 earnings per share expectations. 

C posted disappointing results in investment banking and market revenue, which offset strong results in its treasury and trade solutions and securities services businesses.

UnitedHealth 

UNH

 stock added more than 3% in pre-market trading, after the healthcare giant surpassed Q2 revenue estimates by nearly $2B. 

The group’s overall customer base stood at 152M as of June 30. However, the managed care firm narrowed its full year adjusted earnings per share guidance, while showing signs of rising medical costs.

Shares of Plug Power 

PLUG

 were among the most active ahead of the opening bell, gaining more than 7%. The stock got an upgrade from Northland Securities, with the brokerage believing that the company now had a clear path to cash flow generation. 

Northland also said that PLUG's momentum was picking up with every incremental deal announcement.