"Explaining" the day-to-day MSB share price is beyond me, however I would note the following points:
(1) a "green day" on the market means nothing - I have run daily correlations of the MSB share price vs the market over the short and long term and the correlation is not statistically significantly different from zero. There are dots all over the page, and the fitted correlation on excel averages out around zero over different time frames. While most of the dots are in a regular circle around zero, there are days when the market is up several percent and MSB is down several percent, and vice versa. Likewise, the overnight trading on the US market has no bearing on how MSB will trade the next day in Australia, and vice versa (unless there is a big announcement when one market is shut).
(2) Buy orders exceeding sell orders doesn't mean anything either. It is the aggression of the buyers and sellers that is more important (see point 4). Most of the volume to be bought or sold is not loaded into the screens (e.g. as buyers/sellers try to hide their true intentions so as to get the best price). Often a large buy or sell order that is loaded into the screen is really someone trying to psyche-out the market, implying that they have a lot more to buy or sell. If done in a concerted attack, this may be considered market manipulation by the regulators (have a look at the case against Bell Potter by the corporate regulator last year in relation to the Direct Money float).
(3) Short sellers often load a large number of shares onto the sell side a few cents above the recent price to make it look like there's a lot of selling. They try to keep a lid on the price in this way (and hope they don't get hit by sudden buying). MSB is one of the most shorted stocks on the ASX - it is currently the 20th most shorted stock (with 40.5m or 8.13% of the shares short) and the 11th most shorted stock in terms of days to cover the short position (78 days) according to
https://www.marketindex.com.au/short-selling. Note that "days to cover" is a volatile measure and depends on current low trading volumes - ie if you assume trading volumes regain a more normal 1m shares per day, then it would take 40 trading days to cover -which is still very high and would rank MSB as the 36th most shorted stock on that basis. And you couldn't cover the position in 40 days of 1m per day volume as that assumes ALL the buying is short covering (which is unrealistic as there will always be long buying).
(4) Aggression of buyers and sellers is more important than number of shares disclosed on the buy and sell lists. At time of writing, MSB has 78,000 shares on the bid side at prices of 131.5, 131 and 130.5. The sell side has only 5200 on the offer at 132, 132.5 and 133. Last sale was 131.5. The sellers may have 1m shares they want to sell, but have only disclosed 5200 and they may be waiting for buying to build up in the screen before they hit it. If they are desperate to sell, they could immediately sell it down to 130.5 and move 78,000 shares - and they could sell it all the way down to 120 if they wanted, but that would attract the attention of the regulators and they may be accused of market manipulation if this were part of a pattern of behaviour. Similarly, the buy side could push the price up to 140 by buying around 270,000 shares. of course, big price moves on the upside pull out more sellers and vice versa - so the price is unlikely to stay at these levels for long as new buyers or sellers are attracted by the price action.
(5) A lot of trading occurs at "the midpoint" - you can load in buying or selling at the midpoint and then get hit by a lot of volume which is hiding there.
(6) There is also trading on other platforms such as CHI-X, dark pools, overnight trades, CFDs, options etc, and the company itself can be a source of large quantities of shares in a placement or rights issue. There have also been times when large shareholders have exited in large placements direct to instos (eg Teva's exit) - thus you may see tens of millions of shares put through the market in a large block trade but they were never on the buy or sell lists disclosed o the ASX. The share price will fall heavily if this happens as these type of placements are usually done at a discount if being sold to instos - although MSB has managed to place stock at a premium to the prevailing share price in the past 12 months with NovaQuest and Tasly, which tended to push the share price higher at the time (and these placements obviously don't sit on the buy and sell lists in the screens!).
(7) Instos may trade a portfolio as a principal trade with a broker, and the broker hedges it with SPIs and then tries to unwind it at a profit - if there is a holding of MSB in a portfolio, the broker may just dump it if they have sold everything else for a profit and they want to clear the position. The insto has therefore effectively exited the stock without having to deal it in the market, but makes the problem the broker's.
(8) Funds with large lines to buy and sell can usually get more volume in the opening and closing match (10am and 410pm) and that's often when they get more aggressive. Mostly they try to deal around the VWAP on the day, but index funds may just want to deal at the closing price if they are trying to invest a large new inflow of money (their performance is usually measured from the index level at the end of the day that they received the inflow - so you may see a jump in the closing price on days index funds are buying - although MSB is in very limited indices at very low percentages at present, so this won't be much of a factor yet).
SUMMARY:
The buy and sell lists don't include a lot of what's really going on in the stock. During the day there can be desperation buying and selling and the volumes on the bid and offer can easily be swamped by aggressive buyers and sellers. There are a lot of games going on with MSB as it is tightly held and one one of the most shorted stocks in Australia. Most funds aren't in MSB as it is still speculative, it is burning cash, making losses and doesn't pay a dividend, so it doesn't meet their minimum requirements. Furthermore, it isn't in most of the indices that instos benchmark themselves against, so they can't own it.
This can be a two-edged sword. If MSB does a partnering deal with a large pharma company (as they have been constantly reporting they are working on) then cash flows would turn positive, profits would start to flow and the valuations that most analysts have put on MSB (anywhere up to $A6 per share) would start to be realised. Shorts would be squeezed and the price would be rising for 2 to 3 months of possibly aggressive short covering. Under that scenario, even if the price were rising rapidly, the number of sellers in the screen could be large as investors take advantage of strong buying, and the number of buyers in the screen could stay small as short coverers would not want to advertise their ongoing need to buy. They would try to buy on competing platforms like CHI-X, principal trade direct with brokers/investment banks, sit in the mid-point with undisclosed buying etc. The one thing they won't be able to do is cover their shorts with a big discounted company share placement as MSB has enough cash to keep going until the end of this year - these placements were a feature in the past and made MSB a very attractive stock to short sell, but the progress in trials and backing of US debt specialists and new partners like Tasly have changed the dynamic.
Finally, don't worry about daily fluctuations in the share price, and don't think you can predict them by looking at the number of shares on the bid and offer in the screens (or by watching the overnight US share price). There are much bigger moves afoot. A big US or European pharma partner (with big upfront payments and probably more placements of shares at a premium) would change the game for MSB, would give the technology credibility and would quickly push the share price up towards the big US analysts' valuations.