U.S. stocks were slightly lower at Friday's opening bell as investors await an announcement on Greece's bailout talks. Shares of Deere (DE) started the day lower after warning of a 17% drop in sales for 2015. The farm-equipment maker cited weak global demand, but did report earnings for last quarter that were well above estimates. Walmart (WMT) is looking to extend Thursday’s big losses. The stock was just downgraded by Barclays to EQUAL WEIGHT from OVERWEIGHT on its view Walmart will not see near term benefits from wage increases to offset the higher expenses. Apple (AAPL) is secretly targeting 2020 to go into car production, according to a Bloomberg report citing anonymous sources. The move would put the tech giant head to head with Tesla (TSLA) and General Motors (GM). Both automakers are developing new electric vehicles to launch by 2017.