The Indian rupee is extending upside in opening trades on Thursday, sustaining rally for the fourth straight session. However, lower opening in equities tracking global cues could limit gains in the counter. Rupee opened at Rs 85.48 against the dollar but edged down to hit a low of 85.55 so far during the day. Yesterday, rupee settled with a gain of 15 paise at 85.66 against the US dollar boosted by the renewed inflow of foreign funds and a weak American currency. The dollar index extended deep loses to hit a fresh 3-year low amid mounting concerns over the economic fallout from potential new U.S. tariffs. Meanwhile, positive domestic macroeconomic numbers triggered a buying rush in equities, strengthening the local currency. The benchmark S&P/BSE Sensex rose 309.40 points, or 0.40 percent, to 77,044.29 amid expectations that signs of moderation in domestic inflation, especially core inflation, could pave the way for more RBI rate cuts in the coming months. The broader NSE Nifty index closed up 108.65 points, or 0.47 percent, at 23,437.20 while the BSE mid-cap and small-cap indexes gained 0.6 percent and 0.9 percent, respectively.