The challenge with bonds is not the lot-size, that is solved already on BSE/NSE.
As is evident from NSE/BSE there is not much participation even with reduced lot-size.
The challenge is the sheer number of bonds.
Take the case of Govt. bonds itself.
There are more than 1500 Govt. bonds that offer the same level of sovereign guarantee
just with varying returns and maturity schedules.
IMHO, it is not possible for individuals to monitor that many number of bonds manually.
AFAIK, there aren’t any popular products
that allow individuals to express their interest in the bond market.
I think there is a need for a product
that enables an indvidual to say the following -
Hello other individuals on the exchange,
i have N Lacs and i will buy any bond in this list [A, B, C, …] you may sell
that mature anytime upto the next X years
at a rate such that i effectively receive atleast Y % (dividend + capital-gains)
Note: I end-up doing part of the above using a script that monitors Ask/Bids on NSE/BSE,
and manually placing bids using Limit orders whenever someone offers Govt. bonds on the exchange.
IIUC, the challenge in creating the above product is NOT the tech.
Rather, consider an user that has cash N lac,
how does one provide them a margin to simultaneously bid for (Delivery order) of N lac on 100-200 similar bonds,
with the assumption that the user is happy to purchase a total of N lac worth of any of these bonds.
(i.e. buy N lacs worth of any of the bonds on the user list that get offered for sale on the market first.)
Note, that it is important to not just enable the user to buy the bonds,
but, also important to publicly express their interest to buy certain bonds.
i.e. enable the user to simultaneously bid on each of the bonds in the market
so that any potential sellers of any of the bonds know that that there is interest in buying at a specific rate.
Another, subsequent challenge is the tight circuit-limits (5-10%) in exchanges around bonds
that prevent buyer-seller interested at trading bonds at a significant discount / premium.