According to this Wall Street Journal item, the number of companies disclosing anti-pledging policies so far this proxy season has increased to 107 from just 8 last year:

Proxy-advisory firm Institutional Shareholder Services said in November that it could begin looking at any hedging or pledging of company stock by executives as a “failure in risk oversight,” since a margin call could force executives to sell their stock at an inopportune time. ISS said it would consider whether companies disclosed an antipledging policy in their proxies, but could recommend that investors vote against corporate directors if there is “significant” pledging.