a shift is emerging in silicon valley, with nvidia's stock reaching record highs. the chipmaker dominates the ai market — and its valuation has just breached the 3 trillion dollar mark. it has now overtaken apple to become the world's second most valuable company. the bbc�*s erin delmore has the details from new york. wall street's on a record breaking run. the latest all time high closes for the s&p 500 and the nasdaq. the latter powered by, you guessed it, nvidia. the chip makerjoined the $3 trillion club on wednesday, overtaking apple as the world's second most valuable company. microsoft is still the world's number one. nvidia is only the third company to ever exceed $3 trillion in market value. it's leading in the race to develop the chips needed to enable new artificial intelligence applications. and that's where the other tech giants and a lot of companies are spending big bucks right now.