"я забыла написать, что Mortgages Backed Securities всегда считались очень safe ( это вам не SWAPS или еще какие-то complicated investments)"

Lina, the statement above brings up the notion that you don't exactly understand what you are talkig about. It's a complicated financial instrument, so it's not unusual. Just don't alk about it, it wekens your position.
Swaps are not risky. Quiet the opposite, swaps are used to hedge your risky investment. To explain, you use swaps to minimize your risky exposure. You swap fixed for rate. Foreign currency for dollars. Just a way to hedge your risky positions. Please stick to wat you know,

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Не успело стать хорошо, как кончились деньги..