By default SD supports the use of negative rates in both the yield curves and the OIS curves that are used to price the following linear instruments—vanilla swap, general swap, cross currency swap, forward rate agreement, IMM swap, zero coupon swap, BMA swap, loan and single leg. This means that SD can build the relevant curves even if all of the currency’s interest rates are negative. This is useful, for example, for the CHF OIS curve.
If required you can choose to deactivate this feature for your user, i.e., instruct the system to not use negative rates for the pricing of the supported linear instruments.
You do this in the Settings window in the Default Settings tab > General tab by unchecking the Use Negative Rates checkbox. For more information on working in the General tab, see Customizing Your Default Settings.
If you choose to not use negative rates, note that if all of a currency’s underlying interest rates are negative you will not subsequently be able to access its yield curve or OIS curve. In addition, you will also not be able to calculate a supported linear instrument for that currency.