1) to avoid future potential sanctions
2) a trial-run to gauge how the market would react to a similar move by China.
At its peak Russia held less than $0.2T, Russia liquidated approx $50B per month for 3 months. If China dumped $75B per month for 6 months, there would be pain that would likely spread into corporate bonds.
https://money.cnn.com/2018/07/30/investing/russia-us-debt-tr...
https://www.bloomberg.com/view/articles/2018-10-16/russia-s-...
(edit: formatting)
The Kremlin may be trying to pull off a balancing act by mostly shifting its cache offshore, rather than selling outright.
Analysts at the Council of Foreign Relations this week found that holdings of American bonds in Belgium and the Cayman Islands increased by about $45 billion in the same period that Russia was reducing its U.S.-based hoard, meaning it may have been an attempt to protect against seizure.
https://www.bloomberg.com/news/articles/2018-08-15/russian-g...
I had assumed (without evidence) it was the US. A plunge protection team of sorts.
ZH suggest the buyer was China.
https://www.zerohedge.com/news/2015-05-18/revealing-identity...
That is unlikely to be the result. The US national debt is over $21T now. $1T is <5%. Dumping that much on the market at once would certainly affect interest rates, but not at a catastrophe-inducing level, and all of the normal tools used to control interest rates remain available.
By comparison, the US deficit this year is ~$0.8T, i.e. the US itself is dumping nearly that amount into the market. The Quantitative Easing program after the housing crisis was $3.5T over a few years.
It's also unlikely that they would dump the entire amount at once, because causing a sudden short-term rise in interest rates is not to their advantage (they would take a bath on bond prices). But if they divested something like $100B/year, the effect on the market would be minimized.