The All Ordinaires Index (ASX: XAO) is having a cracker of a day today. At the time of writing, the All Ords is up an impressive 2.4% and is back over 7,300 points. But that is nothing compared to the performance of the Zip Co Ltd (ASX: ZIP) share price.
Zip shares have exploded today. The ASX's largest buy now, pay later (BNPL) share is up an extraordinary 18.4% at the time of writing to 74 cents a share. This comes after Zip shares closed at 62 cents yesterday and opened at 69 cents each this morning.
So what on earth has happened to Zip that has invited this incredible revaluation from investors?

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Why is the Zip share price rocketing 18% today?
Well, it's nothing to do with anything out of Zip itself, it would seem. The company hasn't released any ASX announcements since the results of its annual general meeting on 3 November. And investors reacted sceptically to the company's investor presentation at the time.
However, we are seeing ASX tech shares boom in value across the market today. Block Inc (ASX: SQ2) shares are up more than 12%. Megaport Ltd (ASX: MP1) shares have enjoyed a 13% or so rise, and the WiseTech Global Ltd (ASX: WTC) share price is up more than 9%.
This comes after a stunning night on the US markets overnight. As my Fool colleague flagged this morning, the US S&P 500 Index (SP: .INX) rose by a stunning 4.7% during last night's trading session. The NASDAQ-100 Index (NASDAQ: NDX) Index did even better, lifting by a jaw-dropping 7.5%.
These moves came after some better-than-expected inflation figures out from the US economy, which points to the possibility that interest rates might not rise as high as feared.
ASX shares, particularly tech shares, tend to be highly partial to the moves that their US counterparts make at any given time. So with such a strong showing stateside, the ASX was always going to have a good day. That is probably what is happening with the Zip share price this Friday.
Zip was probably in line for some of the best gains due to its miserable performance over 2022 thus far. Even after today's incredible gains, the company remains down by a painful 82.9% over 2022 year to date.
So this might be why investors are in such a forgiving mood over the Zip share price today.