https://www.reuters.com/article/us-dropbox-results/dropbox-writes-down-real-estate-value-in-transition-to-remote-working-idUSKBN2AI2YD >Dropbox on Thursday posted a bigger fourth-quarter loss, hit by about $400 million of impairment charges on its real estate assets as the file hosting service transitions to a 'virtual first' working model and prepares to sublease parts of its offices.