Tap and toilet manufacturer GWA International is among the share market's most shorted stocks. It's also attracting investors who see potential in the company's role in greening office buildings. Up, down, sideways: few issues get more heated than the future direction of the residential housing market. Which goes some way to explaining the division around toilet and tap manufacturer GWA International, the company that brought the dual flush loo to Australia. The $1 billion company - often dismissed as a "boring industrial" - is now among the market's 10 most shorted stocks, though that short interest has eased slightly since November when it peaked at 15 per cent, according to shortman.com.au. The owner of the bathroom brand Caroma and New Zealand's Methven, said stronger signs were emerging that the housing market could return to growth in 2021. Helpfully too, the coronavirus wasn't affecting supply from Chinese plants so far. GWA shares are far above their $2.88 October lows, having nearly reached $4 in the past weeks, before falling back slightly after the results.