The duo was arrested last Sundayfrom a quarantinefacility at Mahabaleshwar in Satara district, nearly 50 daysafter they were booked in a case of bribery against former YesBank CEO Rana Kapoor.
The Wadhawans were produced before a special courthere on Friday as their previous remand ended.
The central probe agency sought their further custodysaying that it needed to probe the "deeper conspiracy" betweenthe Wadhawans and Kapoor.
The agency alleged that there are more than 150 shellcompanies controlled by the Wadhawans, which they want toexamine.
Besides, there are several companies floated by RanaKapoor and his family and it needed to check whether they(Wadhawans) had any transactions with these companies, theagency said.
Defence advocate Subodh Desai opposed the CBI's pleasaying their custody was not required as everything was onrecord.
However, the court extended the custody till May 8.
The Wadhawan brothers are named as accused in the CBIFIR pertaining to swindling of money by Kapoor and others, theofficials said.
The agency has alleged that Kapoor, 62, entered into acriminal conspiracy with Wadhawan for extending the financialassistance to DHFL through Yes Bank in return for substantialundue benefits to himself and his family members throughcompanies held by them.
According to the CBI FIR, the scam started takingshape between April to June, 2018 when Yes Bank invested Rs3,700 crore in short-term debentures of the scam-hit DewanHousing Finance Corporation Ltd (DHFL).
In return, Wadhawan allegedly "paid kickback of Rs 600crore" to Kapoor and family members in the form of loans toDoIT Urban Ventures (India) Pvt Ltd held by the wife anddaughters of Kapoor.
Besides the CBI, the duo was also being probed by theEnforcement Directorate in connection with the Yes Bank scam. AVINP NP