Please find enclosed disclosure.

IDFCFIRSTBANK/SD/153/2026-27 October 17, 2026 National Stock Exchange of India Limited BSE Limited Mumbai 400 051 Mumbai 400 001 NSE Symbol: IDFCFIRSTB BSE Scrip Code: 539437 Sub.: Disclosure under Regulation 30 of the SEBI (LODR) Regulations, 2015, as amended. Dear Sir/Madam, Pursuant to Regulation 30 of the SEBI Listing Regulations, we wish to inform that Crisil Ratings have re-affirmed ‘CRISIL AAA/Stable’ rating, ‘CRISIL AA+/Stable’ rating and ‘CRISIL A1+’ rating assigned to Fixed Deposits amounting to ₹ 1,60,000 crore, Tier II Bonds (Under Basel III) amounting to ₹ 8000 crore and Certificate of Deposits amounting to ₹ 45,000 crore, respectively. A detailed Rating Rationale for the above is enclosed herewith. Request you to take the above on record. Thanking you, Yours faithfully, For IDFC FIRST Bank Limited Satish Gaikwad General Counsel and Company Secretary Encl.: as above IDFC FIRST Bank Limited Corporate Office: IDFC FIRST Bank Tower, (The Square), C-61, G Block, Bandra-Kurla Complex, Bandra (East), Mumbai - 400 051, Maharashtra. Tel: +91 22 7132 5500 Registered Office: KRM Tower, 7th Floor, No. 1, Harrington Road, Chetpet, Chennai 600 031, Tamil Nadu. Tel: +91 44 4571 6477 CIN: L65110TN2014PLC097792 | E-mail: bank.info@idfcfirstbank.com; | Website: www.idfcfirst.bank.in 10/17/26, 4:57 PM Rating Rationale Rating Rationale October 16, 2026 | Mumbai IDFC FIRST Bank Limited Ratings Reaffirmed Rating Action Instrument Ratings Regulator Of Instrument Rs.160000 Crore Fixed Deposits Crisil AAA/Stable (Reaffirmed) + Tier II Bonds (Under Basel III) Crisil AA+/Stable (Reaffirmed) SEBI Aggregating Rs.8000 Crore Rs.45000 Crore Certificate of Crisil A1+ (Reaffirmed) RBI Deposits Note: None of the Directors on Crisil Ratings Limited’s Board are members of rating committee and thus do not participate in discussion or assignment of any ratings. The Board of Directors also does not discuss any ratings at its meetings. 1 crore = 10 million Refer to annexure for Details of Instruments & Bank Facilities Detailed Rationale Crisil Ratings has reaffirmed its ‘Crisil AAA/Crisil AA+/Stable/Crisil A1+’ ratings on the debt instruments and fixed deposits of IDFC First Bank Limited (IDFC FIRST). The ratings continue to be driven by steady scale up of business, backed by strengthening of both retail asset base and liability franchise, and healthy capitalisation. These strengths are partly offset by profitability remaining constrained by relatively higher operating expenses and credit costs. As on June 30, 2026, the bank's fixed deposits (FDs; including compound interest) stood at Rs 1,40,913 crore, registering a growth of 8.7% over the preceding 12 months, and accounting for 40% of the total external liabilities. The depositor profile for FDs remains granular, with ticket size below Rs 3 crore accounting for 60% of the overall FDs as on June 30, 2026. Moreover, the maturity schedule of outstanding FDs is well staggered with the share of deposits having a tenure of more than nine months stood at 92% as on June 30, 2026. Please refer to Crisil’s criteria for rating fixed deposit programmes for further details. IDFC FIRST’s funded assets grew 20% year-on-year to Rs 2,90,278 crore as on March 31, 2026, from Rs 2,41,326 crore as on March 31, 2025. Within this, the bank’s retail, rural and MSME funded assets grew 18% year-on-year to Rs 2,32,394 (80% of total funded assets as on March 31, 2026). The bank’s overall funded assets grew further to Rs 3,05,370 crore as on June 30, 2026, of which retail, rural and MSME funded assets were Rs 2,41,118 crore (79% of the total funded assets). Furthermore, the bank’s liability franchise remains strong, with current account and savings accounts (CASA) forming 50.8% of total deposits as on June 30, 2026. Retail customer deposits have cumulatively grown by 17% to Rs 2,23,899 crore as on March 31, 2026. Overall deposits have grown by 17% during fiscal 2026 and 24% (annualised) over the first quarter of 2027 to Rs 3,11,892 crore as on June 30, 2026. The bank’s overall gross non-performing assets (GNPAs) stood at 1.61% (Rs 4,559 crore) as on March 31, 2026, as against 1.87% (Rs 4,434 crore) as on March 31, 2025. Over the first quarter of fiscal 2027, GNPA improved further to 1.51%, driven by improved asset quality across both the retail and wholesale portfolios. Improving asset quality resulted in lower credit costs of 1.4% in fiscal 2026 compared with 1.7% in fiscal 2025. However, return on average assets (RoA) remained subdued at 0.4% (0.5% in fiscal 2025) due to lower net interest margin (5.7% of average total assets in fiscal 2026 as against 6.0% in fiscal 2025) and the Rs 646 crore one-time deposit fraud-related loss incurred during the year. In the first quarter of fiscal 2027, the RoA recovered to 1.1% (annualised) supported by lower credit costs as well as operating expenses. As per the bank's provisional business update for September 30, 2026, advances, including FCNR (B) loans, grew 29.9% year- on-year to Rs 3,38,749 crore, while total deposits increased 25.9% to Rs 3,48,582 crore. The CASA ratio stood at 47.6%. Analytical Approach Crisil Ratings has combined the business and financial risk profiles of IDFC FIRST and its subsidiaries. This is because of majority shareholding of the bank in the subsidiaries, business and financial linkages and shared brand. Please refer Annexure - List of Entities Consolidated, which captures the list of entities considered and their analytical treatment of consolidation Key Rating Drivers - Strengths Healthy capitalisation Capital position of the bank is healthy in relation to its scale and nature of business, as reflected in Tier 1 capital adequacy ratio (CAR) of 13.3% and overall CAR of 15.1% as on June 30, 2026 (13.7% and 15.6%, respectively, as on March 31, 2026). Capitalisation is supported by timely capital raises with the last one being Rs 7,500 crore in fiscal 2026 after Rs 3,200 crore raised in fiscal 2025. On June 30, 2026, the bank’s consolidated networth was sizeable at Rs 48,776 crore, thereby providing https://www.crisilratings.com/mnt/winshare/Ratings/RatingList/RatingDocs/IDFCFIRSTBankLimited_October 16_ 2026_RR_407379.html 1/9 10/17/26, 4:57 PM Rating Rationale cushion against asset-side risks, with networth coverage for net NPAs of 37.9 times as on that date. (Rs 47,404 crore and 35.2 times, respectively, as on March 31, 2026). As the growth strategy remains focused on the retail and non-infra commercial loans portfolio with a corresponding scale down of the legacy infrastructure loan portfolio, the bank’s capital consumption is expected to remain limited. However, steady state credit costs in the backdrop of the upcoming transition to expected credit loss (ECL) norms and ability to sustain the improvement in profitability alongside scale, remains a monitorable. Strong liability franchise The customer deposits (excluding the certificate of deposits) grew by 17% (year on year) to Rs 2,84,453 crore as on March 31, 2026, from Rs. 2,42,543 crore, a year ago. This was driven by traction in granular deposit franchise of retail customer deposits which grew 17% to Rs 2,23,899 crore as on March 31, 2026. These deposits comprised 79% of total customer deposits as on March 31, 2026. Mobilisation of CASA deposits has been steady, accounting for 49.8% of total deposits (44% of overall resources) as on March 31, 2026, compared with 47% of total deposits as on March 31, 2025. IDFC FIRST’s total deposits grew further to Rs 3,11,892 crore as on June 30, 2026, which is 18% (year-on-year) higher than that as of June 30, 2025. CASA deposits were at 50.8% (45% of overall resources) as on June 30, 2026. Further, during the FCNR(B) mobilization drive of last quarter, the bank has mobilised Rs 34,390 crore worth of FCNR(B) deposits, which formed 10% of its overall deposit base as on September 30, 2026. Over the past few years, the bank has reduced its dependence on wholesale deposits, certificate of depo [Showing first 8,000 characters — download PDF for full document]