Shares of DryShips Inc. changed hands at $3.74 in premarket trade as the reverse stock split took effect, tumbling 12% from the split-adjusted close of $4.25. The stock had closed at 85 cents on Thursday, before the 1-for-5 reverse split took effect. The stock had plunged 51% the past three sessions, after ocean-going cargo vessel company announced the reverse split ahead of Monday's open. That stock had already lost 99.9% of its value year to date through Wednesday, while the S&P 500 has gained 8.8%.