The 1-for-25 ADS ratio change by NuCana plc is a strategic move to enhance liquidity and ensure compliance with Nasdaq's minimum bid price requirement. This reverse stock split is expected to increase the trading price of NCNA's ADSs, although the company cautions there's no guarantee of proportional price increase or improved liquidity. The direct impact on shareholders is neutral in terms of equity, but the potential for increased trading price and compliance with Nasdaq requirements could positively influence investor perception and stock value in the short term.