Surging demand for AI technologies has driven Taiwan Semiconductor Manufacturing Co.'s stock up 36% this year, creating a unique problem for some large investment funds. The rally has increased TSMC's weighting in key MSCI and Taiwan stock indexes to historic highs, with its share of the Taiex nearing 43%. This growth poses a significant risk for fund managers in regions like Europe and Taiwan, where regulations cap a single stock's holding at 10% of a fund's net asset value. As a result, funds benchmarked to these indices, estimated to be worth at least US$100 billion, are structurally forced to be underweight on TSMC. This restriction means they may underperform their benchmarks, unable to fully capitalize on the gains of the market's most influential stock.