Rivian Automotive has boosted its initial public offering price, seeking to sell 135 million shares between $72 and $74 each, the electric-vehicle startup said in an amended prospectus late Friday. Rivian, whose backers include Ford Motor Co. and Amazon.com Inc. , on Monday filed an amendment setting the offer at $62 a share. Rivian is hoping to carve a niche for itself offering EVs for the great outdoors and first filed for the IPO in October.