How I Check the Liquidity of My SGX Stock Holdings
Running a personal balance sheet on Singapore exchange stocks feels very different from tracking their paper gains. A counter can show a tidy double-digit gain on a Friday close and still leave you stuck on Monday morning when the order book is thin. That gap between marked value and realisable cash is what liquidity actually means to me, and it is the single metric I now weigh before any new buy on the SGX.
I started paying closer attention after a Keppel-linked counter sat with a quarter-million-dollar paper profit for weeks. When I finally wanted to lock in some gains, three market days passed before my full sell order cleared without leaving a footprint on the price. That experience pushed me to formalise how I measure cash-readiness across my holdings, instead of relying on the daily change column in my brokerage app.
Liquidity, the way I use the term on this blog, covers three things. How wide the bid-ask spread sits during normal trading, how many shares the book can absorb before price moves noticeably, and how cleanly a position can be wound down without alerting the rest of the market. Each can be measured differently, and I lean on a mix of public data, my own execution notes, and a simple spreadsheet.
Many readers here in Singapore share similar concerns, but I have heard from people in Sydney and Melbourne who hold a sleeve of SGX names through cross-border brokers. With the AUD trading against the SGD in a narrow band lately, the liquidity question becomes pointed for Australians too, because the currency overlay adds another friction layer. If you are weighing how this fits with your overall household balance, my notes on calculating my net worth with CPF balances walk through a related framework that translates reasonably well to ASX holdings.
Why liquidity deserves more attention than price action
Screens full of green tickers give a false sense of progress. Price is a snapshot; liquidity is a process. On the SGX, I have watched the three local banks trade millions of shares a day with spreads of a fraction of a cent, and I have seen small-cap industrial names gap down eight percent on a single distressed seller. The headline price move tells you nothing about which group your stock belongs to.
Australian investors often assume the same habits they know from the ASX carry over, but it rarely does. CBA and the other Big Four sit on turnover that would dwarf almost any Singapore-listed name outside the banks and the Singtel-tier heavyweights. Yet within the mid-cap space on the ASX itself, liquidity thins rapidly once you move past the top fifty. The lesson is identical on both exchanges, just at different scales.
I treat liquidity as a structural risk, similar to how I treat leverage. It does not announce itself until the day I need it, and by then the cost is already being charged. That is why it now lives on the same review checklist as fundamentals and dividends rather than at the bottom of the page. The few minutes saved by skipping it can become hours lost in a messy unwind.
The yardsticks I use to judge a tradable position
Three numbers go into my liquidity score for each SGX stock. The trailing 30-day average daily volume, the typical bid-ask spread quoted in cents, and the depth on the first three price levels of the order book. From these I derive a rough estimate of how many days it would take to liquidate the position using no more than 10% of normal daily turnover.
That 10% rule is a personal limit, not a market rule. It assumes I do not want my sell orders to be the dominant flow on any given day. For a Singapore blue-chip like DBS or OCBC, the entire position clears inside a single session with the rule barely registering. For a smaller industrial name or a freshly listed S-REIT with thin institutional sponsorship, the same position might take a working week and require multiple limit orders at successively lower prices.
Beyond the headline numbers, I keep a short execution journal. Each time I transact, I record what I expected to clear at versus what I actually received, and how long the order stayed open. Over time this gives me a feel for the difference between advertised liquidity and the liquidity I personally experience, which is often the only number that matters when I am the one pressing the sell button.
For the household context, I treat the liquid portion of my portfolio as one input into a broader cash buffer. You can read about how I balance that against specific commitments in renovation costs on a Singapore family budget, where earmarking cash for planned projects forced me to think harder about which holdings could be converted to cash without drama.
Comparing Singapore exchange depth with what I see on the ASX
A quick comparison captures the main differences I notice when I sit on both sides of the trades. It is not a scientific study, just a personal diary exercise kept across Singapore and Australian brokerage accounts.
| Aspect | SGX (Singapore Exchange) | ASX (Australia) |
|---|---|---|
| Core trading hours (AEST) | 11:00 am to 7:00 pm weekdays, plus pre-open from 10:30 am | 10:00 am to 4:00 pm weekdays, plus extended auction |
| Spread on top-tier banks | Typically 1 to 2 cents on the bid-ask | Usually 1 cent on the four majors |
| Average turnover for mid-caps | Often below S$1m a day, occasionally below S$200k | Variable; many industrials below A$500k a day |
| Retail brokerage commission | Around 0.28% of trade value at major online brokers | Flat fees from A$5 to A$20 at discount brokers |
| Settlement cycle | T+2 trading days for most instruments | T+2 trading days for most instruments |
The hours are the biggest practical difference for an Australian working a 9-to-5 in Brisbane or Canberra. Most of my own orders go in during the lunch break or in the early evening before the Singapore close, and I have learned to give them room. Limit orders are far more useful than market orders when the book is quiet, especially for names that trade only a few hundred lots an hour.
The turnover line is where individual outcomes diverge sharply. A mid-cap on the ASX with the same headline market capitalisation as an SGX peer can have a materially thicker order book, partly because of the local super fund and ETF bid. The SGX simply has fewer natural buyers for a name outside the index, which is why I never assume a quoted market cap implies realisable cash at short notice.
Settlement timing, fees and the real cost of cashing out
Spread, brokerage and stamp duties eat quietly into the cash I receive from a sale. On the SGX, I calculate the round-trip cost for any position I plan to hold under three years before I buy. If the expected profit cannot absorb two full round-trips plus spread erosion, the trade is too thin for my taste.
The hidden layer for an investor based in Australia is FX. Conversion from SGD to AUD through a retail bank can clip 50 to 100 basis points off the final number depending on the channel. A multi-currency account at a broker like Interactive Brokers or CMC Markets softens this, but it shifts the cost into other fees I track separately in my spreadsheet.
I also watch the borrowing cost on margin, which only matters on the days I hold using borrowed funds. The combination of FX, brokerage, and a short funding window can quietly turn a 2% position into a flat outcome within weeks. None of this is a deal-breaker on its own, but the stack of small drags is what convinces me to favour liquid names when a choice is on the table.
One habit that has served me well is to dry-run my exit at the start of every quarter. I open the order ticket, type in the size, set a limit at the mid-price, and see whether the whole order would clear in one shot. If it would, the position passes the dry run. If it would not, I ask myself whether I am willing to accept a chunky exit, and that answer usually dictates what I do next.
Reading the tell-tale signs before I trim or hold
Over time a short list of practical checks has emerged, and I lean on it whenever a holding starts to look stale or overweight.
Signs my position is genuinely liquid:
- The full sell quantity clears within a single AEST crossover session.
- The bid-ask spread holds under three basis points even after my trade.
- Daily turnover comfortably exceeds five times my intended exit size.
- The name has continued to trade during recent market stress events.
The reverse of that list is just as informative, and these are the situations where I either reduce gradually or avoid building the position in the first place.
Red flags that suggest cashing out will hurt:
- Three or more limit orders sitting unfilled at successively lower prices.
- Wide intraday swings without a matching volume expansion.
- Heavy reliance on retail rather than institutional flow in the order book.
- Stock has traded flat for months with declining average value per trade.
When a name trips more than one red flag, I prefer to trim in slices over several weeks rather than in one block, accepting a slightly weaker exit in exchange for not announcing my hand. The discipline mirrors how I treat household savings targets, which is something I write about in setting a realistic savings rate when the cash allocation plan needs to absorb stock inflows.
None of this makes me a faster trader. In fact, it slows me down on entries, because I now skip names whose liquidity profile does not match my planned holding size. That trade-off has been the single biggest improvement to my portfolio over the past two years, and it costs nothing to maintain beyond a Friday afternoon spreadsheet update.
If you are weighing your own SGX positions, or comparing them with ASX holdings from a desk in Sydney, set aside an hour this weekend to run the numbers using the framework above. Start with your largest position, work through the 10% rule, and note the gap between marked value and what you would actually clear. That single exercise tends to reshape how you think about the rest of the list, and it puts you in a stronger position before the next sell-off tests the real depth of the order book. Write your own figure down, then come back and refine it next quarter.