Answer:
The maximum rate is 5.65%.
Explanation:
The break-even 30-day repo rate is the rate at which an investor can make zero profit by carrying the following described trading:
Initially raise 30-day repo at x rate; invest in 90-day bill at 5.30%;
As the 30-day repo is matured, raise fund from 60-day bill at 5.10% to repay the 30-day repo;
Then as the 60-day bill matures, use the proceed from 90-day bill to repay the amount.
In other word, we have the below calculation to illustrate the trading:
Amount repay to 02 fund raising ( through 30-day repo and 60-day bill) = Amount receipt from 90-day bill investment
[1 + x*30/365] x [ 1 + 5.1% *60/365 ] = 1 + 5.30% * 90/365
<=> 1 + x*30/365 = 1.004646 <=> x = 5.65%.