...Ratings Affirmed: On Sept. 29, 2017, Fitch Ratings affirmed HSBC USA Inc.'s (HUSI) and subsidiary, HSBC Bank USA, N.A.'s (HBUS) Long-Term Issuer-Default Ratings (IDR) at `AA'. HSBC Finance Corporation's (HBIO) IDR was affirmed at `A+'. The rating action followed Fitch's rating action on HBIO and HUSI's ultimate parent company, HSBC Holdings plc (HSBC). High Support Probability: Fitch views HBUS/HUSI as core operating entities of HSBC Holdings plc (HSBC, rated AA¡/Stable by Fitch) and, as such, the likelihood of institutional support from its ultimate parent is expected to be extremely high. In determining HUSI's importance, Fitch views HUSI's strategic initiatives as aligned with HSBC group and that potential for disposal from its parent to be extremely limited. Reputational risk to HSBC resulting from default by HUSI is high. Accordingly, HUSI's IDR is equalized with its parent. HBIO One Notch Lower: HBIO's IDR is notched one level below HSBC at 'A+', reflecting Fitch's view that HSBC...