BB&T's third-quarter return on average assets (ROA) was a solid 1.23%, its return on average common equity was 9.94%, and its return on average tangible stockholders' equity was 17.01%. Most banks are facing pressure on their net interest margins, with the Federal Reserve keeping its target federal funds rate in a range of zero to 0.25% since the end of 2008, while the central bank in September significantly increased its purchases of long-term mortgage-backed securities, in an effort to keep long-term rates at historically low levels. While BB&T's net interest margin (NIM) held up nicely during the second quarter, what seems to have caused the shares to slide on Thursday and Friday was the company's guidance, that the margin would narrow to "the mid-3.70s% range in 4Q12," because of lower rates being earned on new assets, higher long-term debit cost, and the runoff of assets covered by the Federal Deposit Insurance Corp. loss-sharing agreement, covering nonperforming assets acquired when BB&T purchased the failed Colonial Bank of Montgomery, Ala., in 2009. Following the share price decline, Citigroup analyst Keith Horowitz on Sunday upgraded BB&T to a "Buy" rating, from a neutral rating, although he lowered his price target for the shares to $35 from $36. Horowitz said "We have been on the sidelines with BBT hoping for an entry point as we like BBT's above average profitability and growth, strong balance sheet and risk discipline - all of which make for an attractive long-term investment - but had felt it was fully valued near-term." Horowitz added that like PNC Financial Services Group ( PNC) and U.S. Bancorp ( USB), BB&T "is in the sweet spot in terms of regional banks, as it's large enough to get the best expense leverage, but not big enough to be weighed down by large capital requirements, and still has the option to grow via well-priced acquisitions where we believe opportunities will surface over time." The analyst lowered his 2013 earnings estimate for BB&T by 25 cents a share to $3.00, because of the company's guidance on the net interest margin and purchase accounting. For a quick comparison, PNC's third-quarter ROA was 1.23% and its return on average common equity was 10.15%. PNC's shares closed at $59.42, returning 6% year-to-date, trading for 1.1 times tangible book value, according to Thomson Reuters Bank Insight, and for nine times the consensus 2013 earnings estimate of $6.69 a share, among analysts polled by Thomson Reuters. Based on a quarterly payout of 40 cents, PNC's shares have a dividend yield of 2.69%.