The high-tech industry is planning to amplify its opposition to a tax proposal by the White House. On June 5, about a half-dozen tech trade associations discussed strategy for stopping a tax hike on multinational corporations, which would come if the Obama administration succeeds in changing a law that allows companies to defer taxes on overseas revenue of their subsidiaries. ..... That has led to a lobbying blitz out of Silicon Valley. This week, at least three tech trade associations are flying in executives from their member companies for meetings with lawmakers and White House aides. They will lobby against...