In London's Main Market small-cap stocks on Monday, HydrogenOne Capital Growth PLC emerged as a top performer, climbing 7.3% to 41.00 pence. The fund, focusing on investments in clean hydrogen companies, reported a rise in its net asset value in the first half of 2024, leading to a 0.6% increase in NAV per share. The firm cited a strengthening clean hydrogen sector, noting a 50% surge in green hydrogen production and a 25% rise in investments compared to the previous year. On the positive side, NCC Group PLC saw a 3.0% increase in stock value to 172.60 pence. The cybersecurity firm raised its profit outlook, expecting around £6 million in adjusted operating profit for the four months ending September 30, up from the previous estimate of £3.5 million. Conversely, TT Electronics PLC faced a significant 31% drop in stock price to 98.20p due to operational inefficiencies in North America. The company expects a substantial revenue shortfall in the second half of 2024, impacting operating profits in the region. Despite this, overall sentiment towards clean hydrogen investments remained positive, driven by growth in production and increased sector investments.