RBS Securities, which is a unit of the Royal Bank of Scotland, launched its first ETN for U.S. investors. The fund is linked to the S&P 500, but it contains downside protection in the event that the markets turn south.

The RBS U.S. Large-Cap Trend Pilot ETN (NYSEArca: TRND) tracks the firm’s proprietary index. It returns either the performance of the S&P 500 Total Return index or the yield of three-month Treasuries, depending on how the S&P is doing, say Steve Dew and Olivier Ludwig for Index Universe.

As long as the S&P is above its 200-day moving average, investors will earn S&P returns. If it drops below for five days, the exposure shifts to Treasuries.

Tisha Guerrero contributed to this article.