NEW YORK ( TheStreet) -- A battle emerging between Goldman Sachs ( GS) and a small pension fund in Louisiana signals that a new sheriff is headed to Wall Street - literally and figuratively. A string of lawsuits filed by the Louisiana Municipal Police Employees Retirement System (LMPERS) target Goldman Sachs and question whether its investment bankers are out for their own interests instead of shareholders. With high stake suits currently in court, LMPERS success may turn to a key deterrent against shoddy Wall Street practices as regulators and legislators struggle to keep beat. Already, in the largest U.S. deal of 2011, Kinder Morgan's ( KMI) $21.1 billion acquisition of El Paso ( EP), LMPERS won a crucial ruling against Goldman Sachs and its merger advice, in a court case that unveiled "disturbing" conflicts of interest . Now the fund is at it again, this time targeting WellPoint's ( WLP) $4.9 billion July 9 acquisition of Medicare-focused insurer Amerigroup ( AGP). As with El Paso, not only is the entire merger at stake - so too is Goldman's sterling reputation as a top Wall Street advisor. In fact, there's a twist - a $233 million payment due to Goldman outside of M&A fees -- were the merger to stand in courts. The payment, a warrant contract stemming from Goldman's underwriting of Amerigroup's debt, pays out on any merger agreed prior to Aug 13 and equates to roughly half of the bank's second quarter advisory revenue. LMPERS argues that the payout and Amerigroup's knowing acceptance of Goldman's conflicts, in addition to the company's closed auction process, has shortchanged shareholders. The contest against Goldman shouldn't be seen in isolation. The fund was one of the first to sue JPMorgan ( JPM) for a trading loss that stands at $5.8 billion, and it's been involved in nearly 50 shareholder lawsuits since July 2010. "LMPERS, is, without a doubt, the most prolific filer of shareholder litigation in U.S. history," said a JPMorgan shareholder in court filings, protesting to the expansion of the suit, which is now a class action. Shareholder lawsuits are often portrayed as nuisance, a sort of stockholder extortion, and as endemic of a litigious culture. LMPERS; however, has won many contests and also uncovered some of Wall Street's dirtiest muck in the process. Were judges to continue finding in favor of litigation and against banker and C-Suite dealings, small time investors like LMPERS - it holds roughly $1.3 billion in investments - could be a key deterrent. In the Amerigroup case, Stuart Grant, the leading plaintiff attorney at Grant & Eisenhofer argues that LMPERS is not only acting in accordance with its shareholder rights - the fund is also simply fed up. While Grant says LMPERS is asking to enjoin the Amerigroup deal so that other competing bidders can enter negotiations, he concedes it's a tough place to put shareholders, who are looking at a big payout. "When you have someone who has a financial interest in the transaction, they have to say 'I can't do this," adds Grant. If LMPERS has turned to an aggressor in Wall Street litigation, other forces may also be at work. In July 2010, the fund's actuary more than doubled employer pension contribution rates to 25% from 11%, citing the market downturn and investment losses that increased its unfunded pension liabilities by $382 million, a 12% additional contribution rate. As of 2011, the fund is nearly 60% funded, according to its financial statements. If the fund is going to ask more of sheriffs financially, then bankers should also expect a squeeze. LMPERS General Counsel Randall Roche said in an August interview with TheStreet that the fund takes legal counsel from roughly a dozen firms on its holdings, and that the fund has seen an increase in cases that merit a suit, in recent years.