The BoJ put interest rates up last week, which surprised everyone because they've been an outlier for a long time in having negative interest rates and then a 0

The BoJ put interest rates up last week, which surprised everyone because they've been an outlier for a long time in having negative interest rates and then a 0% rate. That strengthened the currency even more. If the yen strengthens, then it means the goods sold by Japanese companies become more expensive for foreign buyers, so they'll sell less and earn less. Along with fears of the US economy starting to struggle (worse than expected job figures last week) it's a perfect storm. Gains up to this year have been good so for many firms wanting to de-risk they can still sell now and still make a profit.