Tim Brown, co-founder and co-chairman of the sports shoe manufacturer Allbirds, speaks on stage at the OMR digital trade show in the exhibition halls. Marcus Brandt | Picture Alliance | Getty ImagesAllbirds made a surprising announcement Wednesday that it is pivoting from shoes to artificial intelligence. The move boosted shares of the miniscule market cap company — it was valued at about $21 million at Tuesday's close — by more than 400%. The shares, which were under $3 a day ago, jumped to abo...