what time period, without having a significant impact on market pricing? this question highlights two points : there is both a quantity dimension and a time dimension to liquidity. if i try to sell all my securities at once, my impact on the market is likely to be larger than if i break my order up into smaller pieces and sell it over a period of time. however, if i do the latter and sell gradually, there is a risk that the market price moves against me over that period of time, because of news or other people ’ s transactions and i don ’ t get as good an overall price. see for example, < http : / / www. bloombergview. com / articles / 2015 – 06 – 03 / people - are - worried - about - bondmarket - liquidity >. of late, there has also been the occasional column on people who are not worried about bond market liquidity. “ volatility and market pricing ”, speech to citi ’ s 6th annual australian and new zealand investment conference, sydney, 14 october 2014. bis central bankers ’ speeches the quantity and time element of liquidity is often conflated in the discussion of bond market liquidity. hence you can hear that it is currently simultaneously the best of times and the worst of times for liquidity in the bond market. bond market liquidity at the “ top of book ” is, on a number of metrics, 3 as good as it has ever been. that is, my ability to sell a small parcel of bonds very close to the current market price is very good. but the “ depth of book ”, my ability to sell a large parcel of bonds, is nowhere near as good, and worse than its been for quite some time. how can it be that we have both of these two developments? this outcome reflects the evolution of the market over recent years in response to technological changes, regulatory changes as well as institutional appetite for this activity. in terms of technology, there has been a significant increase in the share of electronic trading in bond markets. in the australian market, we estimate that electronic trading accounts for around one - third of trading in the australian government securities market ( though it is considerably less in other domestic bond markets ). in the us, the share of electronic trading is much higher, more than half of turnover. with the increased electronification of the market has come high - frequency trading firms. these firms are providing increased liquidity at the top of the book,

have housing debt other than debt on their own primary residence. in this graph, we have split up the share of people who have any housing debt into those who have only debt on their own home, and those who have some other kind of housing debt ; most, but not all, of this second group also have owner - occupier debt. as you can see, this other property debt is even more likely to be held by high - income earners than owner - occupier debt is. the pattern of rising ownership rates for older age groups does not give everyone comfort that most people will be able to afford a home eventually. people worry that it is becoming harder to achieve home ownership at a given life stage than it used to be. this would be an issue of inequality across cohorts. it is true that home ownership rates have fallen for most age groups over time ( graph 5 ). the overall ownership rate has stayed fairly steady because the population is ageing. it is also true that ownership rates shifted down between 2006 and 2011 ; we ’ ll know what happened in 2016 when the census data come out in a few months. the 25 – 34 age group is typically seen as the core group of first home buyers. we can see that ownership rates in this group have fallen by a bit more than 10 percentage points since the 6 / 12 bis central bankers'speeches 1970s. but we can also see that most of the decline had already happened by the early 1990s, before the big increase in housing prices relative to incomes. what changed during that earlier period was that people started partnering and settling down later in life. the post - war baby boom had been characterised by an anomalously young average age at first marriage. through the 1970s and 1980s, the normal historical pattern started to reassert itself. ownership rates for young people declined as a result, because many people wait to settle down before they buy a home. by saying this, i ’ m not suggesting that people should not worry about whether households can achieve their desired housing tenure. i am suggesting that the situation is more complex than would be suggested by a single - minded focus on a single metric of affordability, such as median housing prices. much of the commentary around the difficulty of achieving home ownership centres on the task of accumulating the deposit. it seems common to assume that everyone needs a 20 per cent deposit when they first buy. this isn ’ t actually true : although lenders require some deposit