Define "the market". They are diversified across the "new tech" sphere, which on average produces mostly losers and a few big winners.

Diversified tech funds or VC funds as a category, which mostly ignore the large cap and mega cap sphere, have historically underperformed the market except for a group of elite VCs.

What this means for Softbank remains to be seen, but the very act of dumping this much money indiscriminately into new tech cos may have juiced valuations to the point of hindering future returns on the basket.