Sterling could slump 11 percent on a trade-weighted basis against a basket of major developed market currencies if Britain votes to leave the European Union on June 23, Goldman Sachs analysts said on Wednesday.
If a "Brexit" happens, which traders fear would hurt the European economy, Goldman analysts said in a research note they expect the euro to weaken 4 percent.
Their latest view on a possible drop in sterling was less severe than a forecast of a 15 to 20 percent fall seen in early February.
Recent polls have given conflicting snapshots on how Britons would vote in the referendum.
Betting odds indicate the implied probability of a British vote to stay in the EU is 62 percent, according to Betfair.
On Wednesday, sterling rose 0.6 percent against the dollar at $1.4204 and gained 0.2 percent versus the euro at 79.25 pence .
The euro was flat at $1.1257 and 119.31 yen