Bloomberg: Hedge fund action: Viking cut its stake in Facebook by more than two-thirds in the first quarter, reduced other tech holdings including Amazon, Netflix and Uber and sold its stake in Square. Its biggest new buys were JPMorgan and AmEx. Friday is the deadline for 13Fs. In other news, London-based Serone Capital was swamped by the price dislocation in CLOs and took a 36% loss in March.