Boeing has announced plans to raise about $19bn, as it seeks to bolster its balance sheet and avoid the risk of its investment-grade credit rating being cut to junk.

Monday’s announcement came barely two weeks after the US aircraft maker revealed its intention to raise up to $25bn in new capital and agreed a $10bn credit facility, in an effort to shore up finances that have been further strained by its largest labour union going on strike.

Boeing said it would sell 90mn common shares, which total just under $14bn based on the stock’s Friday closing price of $155.01. It also plans to sell $5bn of other securities that would convert into preferred shares. The group did not say how much it hoped to raise in total from the offering, but the money would be used for “for general corporate purposes”.