BUDAPEST, Hungary — As U.S. markets were closed for the holiday, Central European currencies firmed in low liquidity on Monday, with the Polish zloty outperforming the area, boosted by the likelihood of earlier-than-expected monetary policy tightening in Poland.

In terms of the euro, the zloty was up 0.23 percent, trading at 4.5070.

“Liquidity is so low,” a Warsaw-based FX trader explained, “that it can create greater rate jumps.” “The zloty is also backed by the central bank governor, who did not rule out the potential of rate hikes for the first time on Friday.”

In an interview, Governor Adam Glapinski stated, “If there are any causes, such as when inflation is driven by demand factors and good economic growth persists, we will raise rates.”

In June, rate hikes in Hungary and the Czech Republic fanned expectations of a faster-than-expected tightening in Poland, boosting the zloty in recent weeks.

On Thursday, the central banks of Poland and Romania will publish their rate decisions, and Glapinski will conduct a press conference at 1300 GMT on Friday.

The Romanian leu rose 0.4 percent to 4.9270 per dollar.

Investors were also looking forward to the release of Hungary’s June CPI data on Thursday.