The index of listed bank stocks in Warsaw dropped 0.8 percent by 1511 GMT.
The bourse's blue-chip index fell even more, one percent, underperforming regional peers, as Poland's heavy-weight PKN Orlen, a volatile stock, led a fall of oil company shares in the region, shedding 2.6 percent.
The shares of Poland's biggest commercial bank PKO BP eased half a percent.
The bank said that it may pay out up to 25 percent of its 2017 net profit as dividend, taking into account KNF's new rules.
"The real reaction (in bank share prices) should be expected early next week, because banking analysts are still working intensively on the new rules' interpretation," said BZ WBK broker Slawomir Kozlarek.
Elsewhere in Central Europe, the shares of Romania's second-biggest bank, Banca Transylvania rose by almost 1 percent after it said it had reached an agreement with Greece's Eurobank to buy its Romanian unit Bancpost.
Regional stocks, after directionless trade this month, were mixed, just like currencies.
The leu rebounded from an initial easing, trading at 4.6415 against the euro, drifting off record lows set earlier this week at 4.6585.
For now it ignored a new clash between the government and the central bank (NBR).
Romanian Prime Minister Mihai Tudose criticised the bank for not intervening to stop the currency's slide.
It weakened in the past weeks due to concern over budget spending, a ballooning trade deficit, rising inflation, corruption cases and a controversial judiciary reform.
It also got hit by a shift in the NBR's policy focus to market interest rates from the currency exchange rate which it had kept in relatively narrow ranges for years.
Just two months ago, premier Tudose criticised the NBR for a rise in interbank interest rates amid a liquidity squeeze.
The leu's weakness was a result of the shift in focus in the NBR's policies on keeping market interest rates close to its benchmark rate, intended to control inflation more effectively.
"It is hard to foresee the interest rate path in that overheated economy. It is not unsustainability, but the risks are priced in the form of risk premia," one Budapest-based trader said.
One Bucharest-based dealer said Tudose's criticism was not surprising, adding that the leu was not expected to weaken past 4.7 against the euro before Christmas, but may reach new record lows.