Gilead Sciences (GILD) closed at $79.07 in the latest trading session, marking a -0.57% move from the prior day. This change lagged the S&P 500's daily gain of 0.76%. Meanwhile, the Dow gained 0.59%, and the Nasdaq, a tech-heavy index, added 1.12%.The HIV and hepatitis C drugmaker's shares have seen a decrease of 1.84% over the last month, not keeping up with the Medical sector's gain of 1.57% and the S&P 500's gain of 2.5%.Analysts and investors alike will be keeping a close eye on the performance of Gilea ...