I've been watching NuBits for a while, so I can help with some of the SWAG numbers.
Disclaimer: I have no official affiliation with NuBits. The below are my own thoughts and opinions, and of course, may be incorrect.
It would be very interesting to know how much they are making on this spread, but lets assume $1,000 per day or about $360,000 per year. Note this is just a SWAG (scientific wild ass guess).
The NuBot actually defaults to a spread equal to the exchange fee, which means no profit at all. For example, on BTER the exchange fee is 0.2%, so the spread there is 0.4% (+/- the fee in each direction). In the best case, the market maker breaks even due to exchange fees. In the worst case, clever arbitrageurs cause losses for the market maker.
Mean while their crypto-currency assets have experienced a capital loss of 50%, also a SWAG.
Most of the lifetime of Nu has seen Bitcoin around $350, so since it is about $200 today, I would estimate current capital losses of about 35%. There has also been a $50,000 dividend paid out, which came out of the asset side of the balance sheet. In addition, some losses (it's unclear exactly how much) have been incurred due to arbitraguers trading against the artificial liquidity provided by the market maker bots. On the other side of the equation, proceeds from the centralized sales of NuShares are sometimes used to prop up the peg, which they call "tier 4" support. See https://discuss.nubits.com/t/finalized-evolution-of-liquidity-operations/618
Since they launched they have sold over $2 million worth of 0% interest bonds.
That $2M number, which I assume came from CoinMarketCap, is roughly number of NBT that was issued to custodians. However, they have not sold all these; my estimate would be $400,000 to $500,000 of sales. Clearer numbers will probably be forthcoming from custodians as they improve their data reporting.